Due to the rise in multi-drug resistant pathogens and other diseases, there is renewed interest in marine sponge endosymbionts as a rich source of natural products (NPs). The South African marine ...environment is rich in marine biota that remains largely unexplored and may represent an important source for the discovery of novel NPs. We first investigated the bacterial diversity associated with five South African marine sponges, whose microbial populations had not previously been investigated, and select the two sponges (Isodictya compressa and Higginsia bidentifera) with highest species richness to culture bacteria. By employing 33 different growth conditions 415 sponge-associated bacterial isolates were cultured and screened for antibacterial activity. Thirty-five isolates showed antibacterial activity, twelve of which exhibited activity against the multi-drug resistant Escherichia coli 1699, implying that some of the bioactive compounds could be novel. Genome sequencing of two of these isolates confirmed that they harbour uncharacterized biosynthetic pathways that may encode novel chemical structures.
The use of molecular tools to manage natural resources is increasingly common. However, DNA-based methods are seldom used to understand the spatial and temporal dynamics of species' range shifts. ...This is important when managing range shifting species such as non-native species (NNS), which can have negative impacts on biotic communities. Here, we investigated the ascidian NNS
,
,
and
using a combined methodological approach. We first conducted non-molecular biodiversity surveys for these NNS along the South African coastline, and compared the results with historical surveys. We detected no consistent change in range size across species, with some displaying range stability and others showing range shifts. We then sequenced a section of cytochrome c oxidase subunit I (COI) from tissue samples and found genetic differences along the coastline but no change over recent times. Finally, we found that environmental DNA metabarcoding data showed broad congruence with both the biodiversity survey and the COI datasets, but failed to capture the complete incidence of all NNS. Overall, we demonstrated how a combined methodological approach can effectively detect spatial and temporal variation in genetic composition and range size, which is key for managing both thriving NNS and threatened species. This article is part of the theme issue 'Species' ranges in the face of changing environments (part I)'.
The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a ...Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites.
Latrunculiidae, a family of sponges characterized by their production of bioactive pyrroloiminoquinone secondary metabolites, exhibits unprecedented conservation of a dominant Betaproteobacterium species. We propose that these Betaproteobacteria represent specialized sponge endosymbionts that have coevolved with their hosts. We also identify a novel Spirochaetae species found only in Cyclacanthia and Tsitsikamma species that may be involved in secondary metabolites biosynthesis in these sponges.
Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven ...molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are
,
,
and
as well as the recently discovered species,
and
. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species
closely resembled those of the known
(chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins.
sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as
(chemotype I) or non- or monobrominated, hydroxylated discorhabdins.
and
produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
The temperate marine sponge,
, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of
sponges using HR-ESI-LC-MS/MS-based ...molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as
and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-
-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a
sponge species, and the first description of distinct chemotypes within a species of the
family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges.
The genus
Tsitsikamma
Samaai & Kelly, 2002 is to date exclusively reported from South Africa. Three species are known from the southern coast:
Tsitsikamma favus
Samaai & Kelly, 2002, from the Garden ...Route National Park Tsitsikamma Marine Protected Area (MPA) and Algoa Bay;
T. pedunculata
Samaai, Gibbons, Kelly and Davies-Coleman, 2003, collected from Cape Recife in St. Francis Bay, and
T. scurra
Samaai, Gibbons, Kelly and Davies-Coleman, 2003, collected from a wreck site in a small bay west of Hout Bay on the west coast of South Africa. Here two new species are described:
Tsitsikamma michaeli
Parker-Nance,
sp. nov.
, a small green purse-like species, collected from Algoa Bay, and
Tsitsikamma nguni
Parker-Nance,
sp. nov.
, from The Garden Route National Park, Tsitsikamma MPA. Additional morphological characteristics, spicule morphology, and distribution records are provided for
T. favus
and
T. pedunculata
from Algoa Bay. The phylogenetic relationship of these five
Tsitsikamma
species is investigated.
Southern Africa occupies a critical position within the southern hemisphere for the study of broadscale global change and the three oceans around South Africa (the Atlantic, Indian and Southern ...Oceans) play a vital role in determining local and regional climate and weather patterns. Oceans and coasts also provide various resources and services (e.g. food and carbon sequestration), but these services are threatened by human activities. Uncertainty of the impact and consequences of these anthropogenic activities makes it problematic to manage marine resources. Given the recent global emphasis on the development of ‘ocean economies’, the exploitation of living (fisheries, aquaculture and tourism) and non-living (oil and gas, minerals, energy) marine resources should be on a scale that is socially and economically justifiable and ecologically sustainable. In 2014, ‘Operation Phakisa’ was launched in South Africa as an initiative to accelerate execution of the National Development Plan. The primary focus of Phakisa is to unlock the economic potential of South Africa’s oceans. This will be achieved through the ‘implementation of an overarching, integrated ocean governance framework for sustainable growth of the ocean economy that will maximise socio-economic benefits while ensuring adequate ocean environmental protection’ by 2019. Marine spatial planning (MSP) is a key component of this integrated governance framework, and the development of MSP legislation during 2016 was prioritised as ‘critical’ to achieving the Operation Phakisa objectives. Accordingly, the Department of Environmental Affairs (DEA) published the Marine Spatial Planning Bill (2017) ‘to provide a framework for marine spatial planning in South Africa’s waters; to provide for the development of the marine spatial plan; to provide for institutional arrangements for the implementation of the marine spatial plan and governance of the use of the ocean by multiple sectors; and to provide for matters connected therewith’.
Algoa Bay, the largest crenulate bay on the southeastern coast of South Africa, is currently one of the most well-studied marine ecosystems in southern Africa. A plethora of endemic marine ...invertebrates inhabits the benthic reefs on the western edge of the Bay in close proximity to South Africa's sixth largest city. Over the past 25 years, South African marine natural products chemists, together with international collaborators from the US National Cancer Institute and other US institutions, have focused their attention on Algoa Bay's benthic marine invertebrates as a potential source of new anticancer compounds. This review commemorates a quarter of a century of marine biodiscovery in Algoa Bay and presents the structures and bioactivities of 49 new and 36 known specialized metabolites isolated from two molluscs, eight ascidians, and six sponges. Thirty-nine of these compounds were cytotoxic to cancer cells
with 20 exhibiting moderate to potent cytotoxicity. Six other compounds exhibited antimicrobial activity. Foremost among the potential anticancer compounds is mandelalide A (
) from the Algoa Bay ascidian
species.
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