Polyketide Synthases in the Microbiome of the Marine Sponge Plakortis halichondrioides: A Metagenomic Update     

Gerardo Della Sala  Thomas Hochmuth  Roberta Teta  Valeria Costantino  Alfonso Mangoni 《Marine drugs》2014,12(11):5425-5440

Sponge-associated microorganisms are able to assemble the complex machinery for the production of secondary metabolites such as polyketides, the most important class of marine natural products from a drug discovery perspective. A comprehensive overview of polyketide biosynthetic genes of the sponge Plakortis halichondrioides and its symbionts was obtained in the present study by massively parallel 454 pyrosequencing of complex and heterogeneous PCR (Polymerase Chain Reaction) products amplified from the metagenomic DNA of a specimen of P. halichondrioides collected in the Caribbean Sea. This was accompanied by a survey of the bacterial diversity within the sponge. In line with previous studies, sequences belonging to supA and swfA, two widespread sponge-specific groups of polyketide synthase (PKS) genes were dominant. While they have been previously reported as belonging to Poribacteria (a novel bacterial phylum found exclusively in sponges), re-examination of current genomic sequencing data showed supA and swfA not to be present in the poribacterial genome. Several non-supA, non-swfA type-I PKS fragments were also identified. A significant portion of these fragments resembled type-I PKSs from protists, suggesting that bacteria may not be the only source of polyketides from P. halichondrioides, and that protistan PKSs should receive further investigation as a source of novel polyketides.  相似文献   

Boundary layer halogens in coastal Antarctica     

Saiz-Lopez A  Mahajan AS  Salmon RA  Bauguitte SJ  Jones AE  Roscoe HK  Plane JM 《Science (New York, N.Y.)》2007,317(5836):348-351

Halogens influence the oxidizing capacity of Earth's troposphere, and iodine oxides form ultrafine aerosols, which may have an impact on climate. We report year-round measurements of boundary layer iodine oxide and bromine oxide at the near-coastal site of Halley Station, Antarctica. Surprisingly, both species are present throughout the sunlit period and exhibit similar seasonal cycles and concentrations. The springtime peak of iodine oxide (20 parts per trillion) is the highest concentration recorded anywhere in the atmosphere. These levels of halogens cause substantial ozone depletion, as well as the rapid oxidation of dimethyl sulfide and mercury in the Antarctic boundary layer.  相似文献   

Human CHN1 mutations hyperactivate alpha2-chimaerin and cause Duane's retraction syndrome     

Miyake N  Chilton J  Psatha M  Cheng L  Andrews C  Chan WM  Law K  Crosier M  Lindsay S  Cheung M  Allen J  Gutowski NJ  Ellard S  Young E  Iannaccone A  Appukuttan B  Stout JT  Christiansen S  Ciccarelli ML  Baldi A  Campioni M  Zenteno JC  Davenport D  Mariani LE  Sahin M  Guthrie S  Engle EC 《Science (New York, N.Y.)》2008,321(5890):839-843

Duane's retraction syndrome (DRS) is a complex congenital eye movement disorder caused by aberrant innervation of the extraocular muscles by axons of brainstem motor neurons. Studying families with a variant form of the disorder (DURS2-DRS), we have identified causative heterozygous missense mutations in CHN1, a gene on chromosome 2q31 that encodes alpha2-chimaerin, a Rac guanosine triphosphatase-activating protein (RacGAP) signaling protein previously implicated in the pathfinding of corticospinal axons in mice. We found that these are gain-of-function mutations that increase alpha2-chimaerin RacGAP activity in vitro. Several of the mutations appeared to enhance alpha2-chimaerin translocation to the cell membrane or enhance its ability to self-associate. Expression of mutant alpha2-chimaerin constructs in chick embryos resulted in failure of oculomotor axons to innervate their target extraocular muscles. We conclude that alpha2-chimaerin has a critical developmental function in ocular motor axon pathfinding.  相似文献   

Risk factors associated with the antimicrobial resistance of staphylococci in canine pyoderma     

Huerta B  Maldonado A  Ginel PJ  Tarradas C  Gómez-Gascón L  Astorga RJ  Luque I 《Veterinary microbiology》2011,150(3-4):302-308

This study reports the susceptibility to antimicrobial agents of staphylococci (n=105) isolated from dogs, and the factors associated with this resistance. The study animals were 23 healthy dogs (group A), 24 with first-time pyoderma (group B), and 27 with recurrent pyoderma that had undergone long-term antibiotic treatment (group C). Staphylococci were more commonly isolated from the pyoderma-affected than the healthy dogs (p<0.0001). Some 78% of the isolates were resistant to at least one antimicrobial agent. Resistance to amoxicillin-clavulanate, cephalosporins (OR 4.29, 95% CI [1.15, 16.3] respectively), enrofloxacin (OR 9.47, 95% CI [1.53, 58.5]) and ciprofloxacin (OR 79.7 95% CI [3.26, 1947.4]) was more common among group C isolates. Some 32% of all the isolates were multiresistant (MR) and 10.4% were methicillin-resistant (MRS). The probability of isolating MRS staphylococci in group C increased by a factor of four (95% CI [1.18, 17.9]) compared to A plus B. Multi-resistant (MR) isolates were obtained more commonly from urban than rural dogs (OR 3.79, 95% CI [1.09, 13.17]). All the MRS staphylococci encountered were obtained from urban dogs and more commonly from male dogs (p=0.07). This study shows that dogs bred in urban habitat, with a history of antibiotic therapy in the past year represents significant risk of being carriers of isolates resistant to methicillin (MRS) and other antimicrobials. These factors should be considered before applying an antimicrobial treatment in veterinary clinics.  相似文献   

Premature losses of leaf area in response to drought and insect herbivory through a leaf lifespan gradientOA     

Sonia Mediavilla  Montserrat Martínez-Ortega  Santiago Andrés  Javier Bobo  Alfonso Escudero 《林业研究》2022,33(1):39-50

Implications of the differences in leaf life span are still subject to debate in the field of ecophysiology. Since leaf traits associated with these differences may be decisive for determining the distribution of tree species, this topic is particularly relevant in the context of climate change. This study analyzes the effects of the differences in leaf life span on premature losses of leaf area owing to insect herbivory and to abiotic stress. Loss of leaf area may be an important determinant of...  相似文献   

Wide Range Applications of Spirulina: From Earth to Space Missions     

Giacomo Fais  Alessia Manca  Federico Bolognesi  Massimiliano Borselli  Alessandro Concas  Marco Busutti  Giovanni Broggi  Pierdanilo Sanna  Yandy Marx Castillo-Aleman  Ren Antonio Rivero-Jimnez  Antonio Alfonso Bencomo-Hernandez  Yendry Ventura-Carmenate  Michela Altea  Antonella Pantaleo  Gilberto Gabrielli  Federico Biglioli  Giacomo Cao  Giuseppe Giannaccare 《Marine drugs》2022,20(5)

Spirulina is the most studied cyanobacterium species for both pharmacological applications and the food industry. The aim of the present review is to summarize the potential benefits of the use of Spirulina for improving healthcare both in space and on Earth. Regarding the first field of application, Spirulina could represent a new technology for the sustainment of long-duration manned missions to planets beyond the Lower Earth Orbit (e.g., Mars); furthermore, it could help astronauts stay healthy while exposed to a variety of stress factors that can have negative consequences even after years. As far as the second field of application, Spirulina could have an active role in various aspects of medicine, such as metabolism, oncology, ophthalmology, central and peripheral nervous systems, and nephrology. The recent findings of the capacity of Spirulina to improve stem cells mobility and to increase immune response have opened new intriguing scenarios in oncological and infectious diseases, respectively.  相似文献