A microbial factory for defensive kahalalides in a tripartite marine symbiosis

Science ◽  
2019 ◽  
Vol 364 (6445) ◽  
pp. eaaw6732 ◽  
Author(s):  
Jindong Zan ◽  
Zhiyuan Li ◽  
Ma. Diarey Tianero ◽  
Jeanette Davis ◽  
Russell T. Hill ◽  
...  
Keyword(s):  
Chemical Defense ◽  
Bacterial Symbiont ◽  
Biosynthetic Enzymes ◽  
Natural Ecosystems ◽  
Free Living ◽  
Complex Molecules ◽  
Marine Symbiosis ◽  
Elysia Rufescens

Chemical defense against predators is widespread in natural ecosystems. Occasionally, taxonomically distant organisms share the same defense chemical. Here, we describe an unusual tripartite marine symbiosis, in which an intracellular bacterial symbiont (“Candidatus Endobryopsis kahalalidefaciens”) uses a diverse array of biosynthetic enzymes to convert simple substrates into a library of complex molecules (the kahalalides) for chemical defense of the host, the alga Bryopsis sp., against predation. The kahalalides are subsequently hijacked by a third partner, the herbivorous mollusk Elysia rufescens, and employed similarly for defense. “Ca. E. kahalalidefaciens” has lost many essential traits for free living and acts as a factory for kahalalide production. This interaction between a bacterium, an alga, and an animal highlights the importance of chemical defense in the evolution of complex symbioses.

scholarly journals Host-Specific Activation of Entomopathogenic Nematode Infective Juveniles

Insects ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 59 ◽  
Author(s):  
Valentina Alonso ◽  
Shyon Nasrolahi ◽  
Adler Dillman
Keyword(s):  
Entomopathogenic Nematodes ◽  
Morphological Changes ◽  
Entomopathogenic Nematode ◽  
Infection Process ◽  
Bacterial Symbiont ◽  
Infective Juvenile ◽  
Free Living ◽  
Initial Infection ◽  
Host Tissues ◽  
Insect Parasites

Entomopathogenic nematodes (EPNs) are potent insect parasites and have been used for pest control in agriculture. Despite the complexity of the EPN infection process, hosts are typically killed within 5 days of initial infection. When free-living infective juveniles (IJs) infect a host, they release their bacterial symbiont, secrete toxic products, and undergo notable morphological changes. Collectively, this process is referred to as “activation” and represents the point in a nematode’s life cycle when it becomes actively parasitic. The effect of different host tissues and IJ age on activation, and how activation itself is related to virulence, are not well understood. Here, we employed a recently developed bioassay, which quantifies IJ activation, as a tool to address these matters. Appreciating that activation is a key part of the EPN infection process, we hypothesized that activation would positively correlate to virulence. Using the EPNs Steinernema carpocapsae and S. feltiae we found that EPN activation is host-specific and influenced by infective juvenile age. Additionally, our data suggest that activation has a context-dependent influence on virulence and could be predictive of virulence in some cases such as when IJ activation is especially low.

scholarly journals Draft Genome Sequences of Two Cultivable Strains of the Bacterial Symbiont Serratia symbiotica

2020 ◽  
Vol 9 (10) ◽  
Author(s):  
François Renoz ◽  
Jérôme Ambroise ◽  
Bertrand Bearzatto ◽  
Patrice Baa-Puyoulet ◽  
Federica Calevro ◽  
...  
Keyword(s):  
Draft Genome ◽  
Bacterial Symbiont ◽  
Genome Sequences ◽  
Free Living ◽  
Content Type ◽  
Obligate Intracellular ◽  
Mutualistic Interactions ◽  
Serratia Symbiotica ◽  
Symbiont Species

Serratia symbiotica, one of the most frequent symbiont species in aphids, includes strains that exhibit various lifestyles ranging from free-living to obligate intracellular mutualism. Here, we report the draft genome sequences of two strains, namely, 24.1 and Apa8A1, isolated from aphids of the genus Aphis, consisting of genome sizes of 3,089,091 bp and 3,232,107 bp, respectively. These genome sequences may provide new insights into how mutualistic interactions between bacteria and insects evolve and are shaped.

scholarly journals Complete Genome Sequence of the Intracellular Bacterial Symbiont TC1 in the Anaerobic Ciliate Trimyema compressum

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Naoya Shinzato ◽  
Hiroaki Aoyama ◽  
Seikoh Saitoh ◽  
Naruo Nikoh ◽  
Kazuma Nakano ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Methanogenic Archaea ◽  
Bacterial Symbiont ◽  
Free Living ◽  
Anaerobic Ciliate ◽  
Trimyema Compressum ◽  
Freshwater Environments

A free-living ciliate, Trimyema compressum , found in anoxic freshwater environments harbors methanogenic archaea and a bacterial symbiont named TC1 in its cytoplasm. Here, we report the complete genome sequence of the TC1 symbiont, consisting of a 1.59-Mb chromosome and a 35.8-kb plasmid, which was determined using the PacBio RSII sequencer.

scholarly journals Concentration of lead, cadmium, and mercury in tissues of European beaver (Castor fiber) from the north-eastern Poland

2014 ◽  
Vol 58 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Aleksandra Giżejewska ◽  
Anna Spodniewska ◽  
Dariusz Barski
Keyword(s):  
Heavy Metals ◽  
Absorption Spectrometry ◽  
Castor Fiber ◽  
Natural Ecosystems ◽  
Free Living ◽  
Tissue Samples ◽  
The North ◽  
North Eastern ◽  
Heavy Metals Contamination ◽  
Agricultural Regions

Abstract The aim of the study was to determine the concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) in the liver, kidneys, and muscles of European beavers (Castor fiber) and thus to evaluate the degree of heavy metals contamination in Warmia and Mazury region in Poland. The study was conducted on free-living beavers captured in region of Warmia and Mazury during autumn 2011. Concentrations of the elements were determined by atomic absorption spectrometry. The presence of the metals was detected in all individual tissue samples. Mean Pb and Hg concentrations were relatively low. However, the high mean Cd level, especially in the kidneys (7.933 mg/kg) and liver (0.880 mg/kg) was demonstrated. Despite the fact that region of Warmia and Mazury is considered to be “ecologically clean”, the conducted studies indicate that systematic monitoring for the presence of heavy metals is necessary not only in industrialised but also in agricultural regions, as well as in natural ecosystems.

Parasitism as the main factor shaping peptide vocabularies in current organisms

Parasitology ◽  
2017 ◽  
Vol 144 (7) ◽  
pp. 975-983 ◽  
Author(s):  
MICHAELA ZEMKOVÁ ◽  
DANIEL ZAHRADNÍK ◽  
MARTIN MOKREJŠ ◽  
JAROSLAV FLEGR
Keyword(s):  
T Cell Receptors ◽  
Lower Number ◽  
Evolutionary Strategy ◽  
Free Living ◽  
Complex Molecules ◽  
Histocompatibility Complex ◽  
Living Species ◽  
Unicellular Organisms ◽  
Living Organisms ◽  
Main Factor

SUMMARYSelf/non-self-discrimination by vertebrate immune systems is based on the recognition of the presence of peptides in proteins of a parasite that are not contained in the proteins of a host. Therefore, a reduction of the number of ‘words’ in its own peptide vocabulary could be an efficient evolutionary strategy of parasites for escaping recognition. Here, we compared peptide vocabularies of 30 endoparasitic and 17 free-living unicellular organisms and also eight multicellular parasitic and 16 multicellular free-living organisms. We found that both unicellular and multicellular parasites used a significantly lower number of different pentapeptides than free-living controls. Impoverished pentapeptide vocabularies in parasites were observed across all five clades that contain both the parasitic and free-living species. The effect of parasitism on a number of peptides used in an organism's proteins is larger than effects of all other studied factors, including the size of a proteome, the number of encoded proteins, etc. This decrease of pentapeptide diversity was partly compensated for by an increased number of hexapeptides. Our results support the hypothesis of parasitism-associated reduction of peptide vocabulary and suggest that T-cell receptors mostly recognize the five amino acids-long part of peptides that are presented in the groove of major histocompatibility complex molecules.

Alkaline Dissociation Products of Lumbricus Terrestris Hemoglobin Viewed with the STEM

1981 ◽  
Vol 39 ◽  
pp. 434-435
Author(s):  
O. H. Kapp ◽  
M. Ohtsuki ◽  
N. Robin ◽  
S. N. Vinogradov ◽  
A. V. Crewe
Keyword(s):  
Carbon Film ◽  
Lumbricus Terrestris ◽  
Uranyl Acetate ◽  
Acetate Solution ◽  
Oxygen Carriers ◽  
Complex Molecules ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Multiple Copies ◽  
Hill Coefficients

Annelid extracellular hemoglobins are among the largest known proteins (M.W = 3.9 x 106), and together with the hemocyanins are the largest known oxygen carriers. They display oxygen affinities generally higher than those o vertebrate hemoglobins with Hill coefficients ranging from slightly higher than unity to values as high as 5-6. These complex molecules are composed of multiple copies of as many as six different polypeptides and posse: approximately 150 hemes per molecule.The samples were diluted to 100-200 μg/ml with distilled water just before application to a thin carbon film (∽15 Å thick). One percent (w/v) uranyl acetate solution was used for negative staining for 2 minutes and dried in air. The specimens were examined with the high resolution STEM. Their general appearance is that of a hexagonal bilayer (Fig. 1), each layer consisting of six spheroidal subunits. The corner to corner hexagonal dimensic is approximately 300 Å and the bilayer thickness approximately 200 Å.

Ultrastructure of neuromuscular relationships in the canine heartworm (dirofilaria immitis)

1986 ◽  
Vol 44 ◽  
pp. 278-279
Author(s):  
W. L. Steffens ◽  
Nancy B. Roberts ◽  
J. M. Bowen
Keyword(s):  
Dirofilaria Immitis ◽  
Domestic Dogs ◽  
Structural Description ◽  
Pharmacological Effects ◽  
Free Living ◽  
Canine Heartworm ◽  
The World ◽  
Synaptic Region ◽  
Muscle Innervation ◽  
Insight Into

The canine heartworm is a common and serious nematode parasite of domestic dogs in many parts of the world. Although nematode neuroanatomy is fairly well documented, the emphasis has been on sensory anatomy and primarily in free-living soil species and ascarids. Lee and Miller reported on the muscular anatomy in the heartworm, but provided little insight into the peripheral nervous system or myoneural relationships. The classical fine-structural description of nematode muscle innervation is Rosenbluth's earlier work in Ascaris. Since the pharmacological effects of some nematacides currently being developed are neuromuscular in nature, a better understanding of heartworm myoneural anatomy, particularly in reference to the synaptic region is warranted.

Lead and lead toxicity in domestic and free living birds

2003 ◽  
Vol 32 (1) ◽  
pp. 3-13 ◽  
Author(s):  
N. De Francisco ◽  
N. De Francisco ◽  
N. De Francisco
Keyword(s):  
Lead Toxicity ◽  
Free Living
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