The bryozoan, Bugula neritina, was found to harbor a Gammaproteobacterial endosymbiont that was proposed to become the true producer of bryostatins that shield the larvae against predators (,). These examples supply evidence that secondary metabolites from time to time are vital in symbiosis. While shipworm symbionts previously have already been shown to contribute to nitrogen metabolism in the host and happen to be proposed to contribute to lignocellulose digestion (,), their possible function as producers of secondary metabolites has not been proposed or explored. Compound and its boronated derivative compound (Fig.) have been isolated from 1 of those shipworm symbionts, T. turnerae T. Perez et al. identified compound from a marine actinomycete species that is certainly phylogenetically distant in the Gammaproteobacteria T. turnerae. These authors also reported the boronated derivative of this compound as a minor contaminant in their original sample, which we’ve got dubbed “tartrolon E” (compound). Tartrolons belong to a group of macrodiolides with wellknown pharmacological activities (Fig. and Table). They are dimers or pseudodimers consisting of two polyketide chains joined as diesters. Members of this group are practically identical in their C-terminal regions, 
differing mainly in oxidation statekirromycin; Lkc, lankacidin; Lnm, leinamycin; Mgs, migrastatin; MICAU, Micromonospora aurantiaca ATCC cluster; Mmp, mupirocin; Mln, macrolactin; MSP, Micromonospora sp. ATCC ; Onn, onnamide; Ozm, oxazolomycin; Ped, pederin; Pel, Peltigera membranaceae cluster; PPA, Plesiocystis pacifica SIR- cluster; Psy, psymberin; Rhi, rhizoxin; SBI, Streptomyces bingchenggensis BCW- cluster; Sor, sorangicin; SG, Streptomyces griseus NPRC cluster; Ta, myxovirescin; Tai, thailandamide; Trt, tartrolon (T. turnerae T); Vir, virginiamycin M.LkcKS -OH (,) Mixed Glycine (,) MlnKS_V BCERKS BTPKS BCERKS BTPKS pyran ring (,) CorKS decreased (,) DszKS_IV CorKS decreased, acetyl -branch (,) reduced or – -double bond (,) CorKS TrtKS lowered with or without the need of -Me (,) TrtKS KS (,) MSPKS PelKS RhiKS KS from Clostridium -MeOH (,) -Me, mostly -OH (,) -branch (,) -Me E double bond (,) L-OH (,) amino acid (,) cis-AT PKS (,) PsyKS MSPKS MSPKS KirKSTrtKSKirKSElsKS DifKS_XV EtnKSDB, KS in form B bimodule (,)TrtKS.KS (,)Fig.ML-reconstituted tree of full-length unedited KS domains from trans-AT PKS enzymes. For clarity, identified clades and clades not relevant to TrtKS were collapsed. The KS domains are numbered according to the occurrence inside the gene cluster starting from PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27602092?dopt=Abstract the finish, as previously establishedThe numbers in parenthesis indicate total quantity of KS domains in the clade, number of KS with recognized function and matching specificity number of KS with unknown functionnumber of KS with recognized function and mismatching specificity, specifically as previously describedAlb, albicidin; Bae, bacillaene (SGC707 cost Bacillus amyloliquefaciens); Bry and BryX, bryostatin; BBR and BBR, Brevibacillus brevis NBRC clusters BBR_- and BBR_-; BCER, Bacillus cereus BSGC E cluster; BT, Burkholderia thailandensis MSMB cluster; Bat, E-982 batumin; BATR, Bacillus atrophaeus cluster; BTP, Bacillus thuringiensis pondicheriensis BGSC BA cluster; CACI, Catenulispora acidiphila DSM ; CC, CC, and CC, Clostridium cellulolyticum H clusters Ccel_-, Ccel_-, and Ccel_-; Chi, chivosazol; Cor, corallopyronin; Dif, difficidin; Dsz, disorazol; Els, elansolid; Etn, etnangien; GU, Geobacter uraniireducens Rf; Kir,E .orgcgidoi..Elshahawi et al.TablePrevalence st.The bryozoan, Bugula neritina, was found to harbor a Gammaproteobacterial endosymbiont that was proposed to become the correct producer of bryostatins that protect the larvae against predators (,). These examples supply proof that secondary metabolites in some cases are essential in symbiosis. Although shipworm symbionts previously have been shown to contribute to nitrogen metabolism inside the host and happen to be proposed to contribute to lignocellulose digestion (,), their prospective function as producers of secondary metabolites has not been proposed or explored. Compound and its boronated derivative compound (Fig.) had been isolated from a single of these shipworm symbionts, T. turnerae T. Perez et al. identified compound from a marine actinomycete species that may be phylogenetically distant from the Gammaproteobacteria T. turnerae. These authors also reported the boronated derivative of this compound as a minor contaminant in their original sample, which we have dubbed “tartrolon E” (compound). Tartrolons belong to a group of macrodiolides with wellknown pharmacological activities (Fig. and Table). They may be dimers or pseudodimers consisting of two polyketide chains joined as diesters. Members of this group are nearly identical in their C-terminal regions, differing mainly in oxidation statekirromycin; Lkc, lankacidin; Lnm, leinamycin; Mgs, migrastatin; MICAU, Micromonospora aurantiaca ATCC cluster; Mmp, mupirocin; Mln, macrolactin; MSP, Micromonospora sp. 
ATCC ; Onn, onnamide; Ozm, oxazolomycin; Ped, pederin; Pel, Peltigera membranaceae cluster; PPA, Plesiocystis pacifica SIR- cluster; Psy, psymberin; Rhi, rhizoxin; SBI, Streptomyces bingchenggensis BCW- cluster; Sor, sorangicin; SG, Streptomyces griseus NPRC cluster; Ta, myxovirescin; Tai, thailandamide; Trt, tartrolon (T. turnerae T); Vir, virginiamycin M.LkcKS -OH (,) Mixed Glycine (,) MlnKS_V BCERKS BTPKS BCERKS BTPKS pyran ring (,) CorKS reduced (,) DszKS_IV CorKS reduced, acetyl -branch (,) lowered or – -double bond (,) CorKS TrtKS lowered with or without having -Me (,) TrtKS KS (,) MSPKS PelKS RhiKS KS from Clostridium -MeOH (,) -Me, mainly -OH (,) -branch (,) -Me E double bond (,) L-OH (,) amino acid (,) cis-AT PKS (,) PsyKS MSPKS MSPKS KirKSTrtKSKirKSElsKS DifKS_XV EtnKSDB, KS in variety B bimodule (,)TrtKS.KS (,)Fig.ML-reconstituted tree of full-length unedited KS domains from trans-AT PKS enzymes. For clarity, known clades and clades not relevant to TrtKS have been collapsed. The KS domains are numbered based on the occurrence inside the gene cluster starting from PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27602092?dopt=Abstract the end, as previously establishedThe numbers in parenthesis indicate total number of KS domains in the clade, variety of KS with known function and matching specificity number of KS with unknown functionnumber of KS with identified function and mismatching specificity, precisely as previously describedAlb, albicidin; Bae, bacillaene (Bacillus amyloliquefaciens); Bry and BryX, bryostatin; BBR and BBR, Brevibacillus brevis NBRC clusters BBR_- and BBR_-; BCER, Bacillus cereus BSGC E cluster; BT, Burkholderia thailandensis MSMB cluster; Bat, batumin; BATR, Bacillus atrophaeus cluster; BTP, Bacillus thuringiensis pondicheriensis BGSC BA cluster; CACI, Catenulispora acidiphila DSM ; CC, CC, and CC, Clostridium cellulolyticum H clusters Ccel_-, Ccel_-, and Ccel_-; Chi, chivosazol; Cor, corallopyronin; Dif, difficidin; Dsz, disorazol; Els, elansolid; Etn, etnangien; GU, Geobacter uraniireducens Rf; Kir,E .orgcgidoi..Elshahawi et al.TablePrevalence st.
