Non-lethal effects of an invasive species in the marine environment: the importance of early life-history stages

Studies examining the effects of invasive species have focussed traditionally on the direct/lethal effects of the invasive on the native community but there is a growing recognition that invasive species may also have non-lethal effects. In terrestrial systems, non-lethal effects of invasive species can disrupt early life-history phases (such as fertilisation, dispersal and subsequent establishment) of native species, but in the marine environment most studies focus on adult rather than early life-history stages. Here, we examine the potential for an introduced sessile marine invertebrate (Styela plicata) to exert both lethal and non-lethal effects on a native species (Microcosmus squamiger) across multiple early life-history stages. We determined whether sperm from the invasive species interfered with the fertilisation of eggs from the native species and found no effect. However, we did find strong effects of the invasive species on the post-fertilisation performance of the native species. The invasive species inhibited the settlement of native larvae and, in the field, the presence of the invasive species was associated with a ten-fold increase in the post-settlement mortality of the native species, as well as an initial reduction of growth in the native. Our results suggest that larvae of the native species avoid settling near the invasive species due to reduced post-settlement survival in its presence. Overall, we found that invasive species can have complex and pervasive effects (both lethal and non-lethal) across the early life-history stages of the native species, which are likely to result in its displacement and to facilitate further invasion.     

High expression of DLL3 is associated with a poor prognosis and immune infiltration in invasive breast cancer patients

BackgroundPrevious studies have shown the prognostic value of delta like canonical Notch ligand 3 (DLL3) in patients with different types of tumors, but the role and predictive value of DLL3 in invasive breast cancer (IBC) have not been reported. In this study, we explored the prognostic ability and potential ways of DLL3 in IBC patients.MethodsWe retrospectively enrolled 130 IBC patients from a single institution from 2004 to 2019 for bioinformatics and statistical analysis. The Cancer Genome Atlas breast invasive carcinoma (TCGA-BRCA) cohort was used for verification.ResultsHigh expression of DLL3 was associated with overall survival (OS) in IBC patients (P = 0.023). Multivariate analysis further showed that DLL3 expression was an independent prognostic factor (hazard ratio [HR]: 1.08; 95% confidence interval [CI]: 1.01–1.15; P = 0.017). Time-dependent receiver operating characteristic (ROC) with the area under the curve (0.786) demonstrated that DLL3 expression can predict the survival outcome of IBC patients. Furthermore, the expression of DLL3 was related to a variety of tumor infiltrating immune cells (TIICs), particularly T cells regulatory (Tregs). Gene set enrichment analysis (GSEA) and immunohistochemistry (IHC) results indicated that DLL3 was closely related to p53 signaling pathway.ConclusionsHigh expression of DLL3 was associated with poor prognosis and immune cell infiltration in IBC patients. Moreover, P53 signaling pathway may be the key pathway.     

First report of the oriental shrimp <Emphasis Type="Italic">Palaemon macrodactylus</Emphasis> Rathbun, 1902 (Decapoda,Caridea, Palaemonidae) from German waters

The native East Asian shrimp Palaemon macrodactylus has become a common inhabitant of estuaries along the Pacific coast of North America. More recently (documented since 1999), the species has also been colonising European waters and has been reported from Spain, England, Belgium and the Netherlands. In this study, we present a chronology of the reported introductions of this species and provide the first detailed report of its occurrence in German waters. P. macrodactylus was found in the Geeste river mouth (Weser Estuary) as well as in Hooksiel, north of Wilhelmshaven between 2004 and 2005. We assume its presence in other estuarine habitats of the North Sea and predict its introduction into the Baltic Sea.     

The first occurrence of the ctenophore <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> in the North Sea

After the discovery of large densities of Mnemiopsis leidyi in the Baltic Sea near Kiel by Javidpour et al. (First record of Mnemiopsis leidyi A. Agassiz 1865 in the Baltic Sea, 2006) in October 2006, we investigated the gelatinous zooplankton in the North Sea near Helgoland and recorded Mnemiopsis leidyi for the first time in the North Sea, albeit in much lower densities than those recorded in the Baltic Sea.     

Spatial and temporal effects of pre-seeding plates with invasive ascidians: Growth, recruitment and community composition

Many shallow water subtidal habitats in Massachusetts, USA have recently been invaded by five non-indigenous ascidian species: Ascidiella aspersa, Botrylloides violaceus, Didemnum sp., Diplosoma listerianum and Styela clava. This study examined the effects of seawater temperature, as a proxy for climate change, on B. violaceus and D. listerianum and the impact these ascidians have on native sessile fouling communities. Field experiments were conducted over a four month period at two locations (Lynn and Woods Hole, MA) to examine growth dynamics over regional thermal and geographic ranges. Invasive ascidians occupied as much as 80% of the primary substratum and accounted for the majority of species richness. B. violaceus and D. listerianum growth were similar at both study sites, but initial colony growth of D. listerianum was positively affected by temperature. B. violaceus and D. listerianum exhibited rapid two-week growth rates during the summer months with more rapid growth at the warmer Woods Hole site. Competition for space between B. violaceus and D. listerianum typically resulted in neutral borders between colonies. Overgrowth occurred if the colony of one species was disproportionably larger than the colony of the other species. Recruitment and growth of native species influenced the long-term composition of experimental communities more than the pre-seeding with B. violaceus or D. listerianum colonies. Elevated temperatures, however, increased initial growth of B. violaceus and D. listerianum and may have facilitated the species success to invade the communities during crucial periods of introduction. With projected global climate change, a rise in sea surface temperatures may exacerbate the cumulative impacts of invasions on benthic communities and facilitate the invasion of other non-native ascidian species.     

Recent population expansions of non-native ascidians in The Netherlands

Over the last 50 yrs seven non-native ascidians have settled in The Netherlands, concentrated in the two periods 1974-1977 and 1991-2004 (i.e., Styela clava, Aplidium glabrum, Diplosoma listerianum, Didemnum sp., Botrylloides violaceus, Molgula complanata and Perophora japonica). The year of the introduction of B. violaceus remains a matter of dispute because many of the Botrylloides specimens that are recorded in western Europe, have been identified as the closely resembling species B. leachi. Only Didemnum sp. has become a true invasive species and has become a threat to native ecosystems, especially in the province of Zeeland, by its ability to overgrow virtually all hard substrata present. This includes rocks, stones, sand, algae and almost all sessile marine animals. The sudden population expansion of the didemnid from 1996 onward, coincided with the cold winter of 1995-1996, which caused decreased population sizes of many marine animals. The resulting increase in the availability of suitable substrates for settlement and the strong decrease of grazing sea urchins, may have triggered the population expansion. Studying its population dynamics, the optimal growing temperature for Didemnum sp. appears to be 14-18 °C. Virtually all colonies die when the water temperature gets colder than 5 °C. Colonies growing on live marine animals seem to be more resistant to the cold, than those growing on rocks, stones and plants. Two potential predators of the didemnid have also been recorded in Dutch waters: the gastropods Trivia arctica and Lamellaria sp.     

Spread of Microcosmus squamiger (Ascidiacea: Pyuridae) in the Mediterranean Sea and adjacent waters

The Mediterranean Sea is subject to an ever-increasing arrival of non-indigenous marine organisms. Microcosmus squamiger is a solitary ascidian that inhabits shallow rocky littoral habitats. It probably originated in Australia and it has shown great invasive potential in other parts of the world. In the Mediterranean, M. squamiger has only been reported at a few sites in Spain and Italy. However, the closely related species Microcosmus exasperatus has been reported in several areas of the western Mediterranean. As these species can be easily confused, we re-examined most of the material from previous studies and our personal collections. In addition, sampling was done at several sites along the western Mediterranean and Atlantic coasts. The results showed that the majority of the M. exasperatus reports correspond to M. squamiger, and that M. squamiger is common on the Atlantic shores. This suggests that M. squamiger has entered the Mediterranean through the Gibraltar Strait, while the restricted distribution in the eastern Mediterranean of M. exasperatus suggests that this species is probably a Lessepsian migrant. In the Mediterranean Sea, M. squamiger has the ability to occupy extensive areas of hard substrata and to outcompete native species. Further studies are necessary to assess what impacts this invasive species have on native communities.     

Influence of angles occlusion in periodontal diseases

It is of interest to document the known relationship between periodontal status and Angle''s malocclusion types. We used 26092 case records of patients between 16 to 50 years of age with no gender restrictions. Variables such as age, gender, periodontal diagnosis and type of Angle''s occlusion were extracted and tabulated. Statistical analysis was completed using chi square test in the SPSS software version 20. Data shows that the majority (95.27%) had Angle''s class I occlusion and less than 5% had class II and Class III occlusion. Statistical analysis of class II and Class III cases with 1000 randomly selected cases of class I occlusion show a significant difference in the periodontal status between different types of Angle''s occlusion. Chronic periodontitis was more in class I (10.4%) and it was the lowest in Class II Div 2 (4.3%) occlusion. Class II Div 1(23.8%) and Class III (17%) had the highest and lowest proportion of clinically healthy periodontium, respectively. Thus, we report that angles occlusion types had significant influence on periodontal status along with the other determinants.