Oridonin effectively reverses the drug resistance of cisplatin involving induction of cell apoptosis and inhibition of MMP expression in human acute myeloid leukemia cells

Cisplatin is the first generation platinum-based chemotherapy agent. However, the extensive application of cisplatin inevitably causes drug resistance, which is a major obstacle to cancer chemotherapy. Oridonin is a diterpenoid isolated from Rabdosia rubescens with potent anticancer activity. The aim of our study is to investigate the role of oridonin to reverse the cisplatin-resistance in human acute myeloid leukemia (AML) cells. The effect of oridonin on human AML cell proliferation was evaluated by MTT assay, cell migration and invasion were evaluated by transwell migration and invasion assays in cisplatin-resistant human AML cells. Furthermore, cell apoptosis was examined by flow cytometry. The inhibitive effect of oridonin in vivo was determined using xenografted nude mice. In addition, the expressions of MMP2 and MMP9 were detected by Western blot. There was a synergistic antitumor effect between cisplatin and oridonin on cisplatin-resistant human AML cells in vitro and in vivo. In addition, the combination of cisplatin and oridonin synergistically induced cell apoptosis. Furthermore, the combination treatment not only inhibited AML cell migration and invasion, but more significantly, decreased the expressions of MMP2 and MMP9 proteins. Our results suggest that the synergistic effect between both agents is likely to be driven by the inhibition of MMP expression and the resulting increased apoptosis.     

Oridonin suppress cell migration via regulation of nonmuscle myosin IIA

Oridonin, which is isolated from Chinese herb Rabdosia rubescens (Hemsl.) Hara, has been implicated in regulation of tumor cell migration and invasion. In this study, treatment with oridonin enhanced the phosphorylation of myosin regulatory light chain (T18/S19) that regulates the ATPase activity of myosin IIA. Meanwhile, stress fibers were significantly more prominent after oridonin incubation, which impaired cell migration in transwell migration assays. All of these effects may be caused by the decreased interaction between myosin IIA and myosin phosphatase complex, but not kinases. Our data provide clear evidence of this novel pharmacological function for oridonin in treating cancer cell migration.     

Oridonin-induced mitochondria-dependent apoptosis in esophageal cancer cells by inhibiting PI3K/AKT/mTOR and Ras/Raf pathways

Oridonin, an active diterpenoid isolated from Rabdosia rubescens, has been reported for its antitumor activity on several cancers. However, its effect on human esophageal cancer remains unclear. In this study, we demonstrated that oridonin could inhibit the growth of human esophageal cancer cells both in vitro and in vivo. Oridonin not only suppressed the proliferation, but also induced cell cycle arrest and mitochondrial-mediated apoptosis in KYSE-30, KYSE-150, and EC9706 cells with dose-dependent manner. Further mechanism studies revealed that oridonin led cell cycle arrest in esophageal cancer cells via downregulating cell cycle-related proteins, such as cyclin B1 and CDK2, while upregulating p53 and p21. Oridonin also increased proapoptotic protein Bax and reduced antiapoptotic protein Bcl-2, as well as the increased expression of cleaved caspase-3, -8, and -9. In addition, oridonin treatment could significantly inhibit the PI3K/Akt/mTOR and Ras/Raf signaling pathway. In vivo results further demonstrated that oridonin treatment markedly inhibited tumor growth in the esophageal cancer xenograft mice model. Taken together, these results suggest that oridonin may be a potential anticancer agent for the treatment of esophageal cancer.     

Design,synthesis and biological mechanisms research on 1,2,3-triazole derivatives of Jiyuan Oridonin A

Two series of derivatives with 1,2,3-triazole as heterocyclic moiety of Jiyuan Oridonin A, a new ent-kaurene diterpenoid which was isolated from genus Isodon rubescens, were synthesized and biologically evaluated. All the derivatives possessed good anti-proliferative activities. Among them, compound 8g was found to significantly induce cell apoptosis and cell cycle arrest in MGC-803 via a series of signals activated by the increased intracellular ROS levels.     

Frequent chloroplast capture among Isodon (Lamiaceae) species in Japan revealed by phylogenies based on variation in chloroplast and nuclear DNA

A recent phylogenetic study based only on chloroplast DNA (cpDNA) variation revealed that populations of an Isodon species are frequently embedded paraphyletically among other Isodon species. This phylogenetic discrepancy between species taxonomy and molecular phylogeny was considered to have resulted from chloroplast DNA captures and/or incomplete lineage sorting. To elucidate which of these factors was mainly responsible for the observed phylogenetic pattern, we performed phylogenetic analyses of multiple populations of Isodon species in Japan using cpDNA variation, three single-copy nuclear genes, and double-digest restriction-site-associated DNA sequencing (ddRAD-seq). Although a species often shared chlorotypes with other species, our phylogenetical analyses based on variation in the three single-copy nuclear genes and the ddRAD-seq data showed that most populations belonging to the same species were monophyletic at the species level, suggesting that chloroplast capture may have frequently occurred between Isodon species. Some populations of an intraspecific taxon were embedded paraphyletically within the species, regardless of the large amount of phylogenetic information in nuclear DNA; this incongruity may have resulted from incomplete lineage sorting.     

Oridonin suppresses gastric cancer SGC-7901 cell proliferation by targeting the TNF-alpha/androgen receptor/TGF-beta signalling pathway axis

Statistics provided by GLOBOCAN list gastric cancer as the sixth most common, with a mortality ranking of third highest for the year 2020. In China, a herb called Rabdosia rubescens (Hemsl.) H.Hara, has been used by local residents for the treatment of digestive tract cancer for hundreds of years. Oridonin, the main ingredient of the herb, has a curative effect for gastric cancer, but the mechanism has not been previously clarified. This study mainly aimed to investigate the role of TNF-alpha/Androgen receptor/TGF-beta signalling pathway axis in mediating the proliferation inhibition of oridonin on gastric cancer SGC-7901 cells. MTT assay, cell morphology observation assay and fluorescence assay were adopted to study the efficacy of oridonin on cell proliferation. The network pharmacology was used to predict the pathway axis regulated by oridonin. Western blot assay was adopted to verify the TNF-α/Androgen receptor/TGF-β signalling pathway axis regulation on gastric cancer by oridonin. The results showed Oridonin could inhibit the proliferation of gastric cancer cells, change cell morphology and cause cell nuclear fragmentation. A total of 11signaling pathways were annotated by the network pharmacology, among them, Tumour necrosis factor alpha (TNF-α) signalling pathway, androgen receptor (AR) signalling pathway and transforming growth factor (TGF-β) signalling pathway account for the largest proportion. Oridonin can regulate the protein expression of the three signalling pathways, which is consistent with the results predicted by network pharmacology. These findings indicated that oridonin can inhibit the proliferation of gastric cancer SGC-7901 cells by regulating the TNF-α /AR /TGF-β signalling pathway axis.     

Abundance and toxicity of Planktothrix rubescens in the pre-alpine Lake Ammersee,Germany

Regular occurrences of the cyanobacterium Planktothrix rubescens have been observed in several lakes that have undergone recent re-oligotrophication, e.g. Lake Ammersee. Planktothrix species are known to produce microcystins, potent phosphatase inhibitors that have been associated with morbidities and mortalities in humans and animals. The aim of this study was to characterise the temporal and spatial abundance and toxicity of P. rubescens in Lake Ammersee.P. rubescens cell densities and biovolumes were calculated via fluorescence image analyses. P. rubescens was present during the entire observation period from 1999 to 2004, albeit at different cell densities. Maximum biovolumes of 45 cm³ m^?2 were observed in May 2001. Filaments were regularly distributed over the entire water column during winter and stratified in distinct metalimnic layers during summer, reaching maximum cell densities of ≤15,000 (winter) and ≤77,000 cells ml^?1 (summer). The results demonstrate that P. rubescens abundance is strongly influenced by water transparency, i.e. illumination in the metalimnion. Moreover, the P. rubescens abundance appears to result from regular phosphate depletion in the epilimnion, possibly additionally benefiting from high nitrogen loads.Microcystin (MC) was detectable in 27 and 38 of 54 seston samples via HPLC and Adda-ELISA measurements, respectively. The main microcystin congeners in the seston samples were [Asp³]-MC-RR and [Asp³,Dhb⁷]-MC-RR. Microcystin concentrations correlated significantly with the respective phycoerythrin (PE)-concentrations. The variation in the MC/PE-ratios was low suggesting that the microcystin production of P. rubescens in Lake Ammersee is consistent and indicates that the appearance of P. rubescens coincides with measurable microcystin levels. Moreover, the observation of pronounced metalimnic oxygen depletions appears to be causally related to recurring high P. rubescens abundance.In conclusion the results suggest that aquatic organisms such as indigenous fish populations (e.g. coregonids) are regularly confronted with potentially adverse P. rubescens densities, which might provide a possible explanation for the often observed impaired health and growth retardation of coregonid populations in P. rubescens containing pre-alpine lakes.     

Discordant patterns of morphological and genetic divergence in the closely related species Schizanthus hookeri and S.?grahamii (Solanaceae)

In this study I have examined the patterns of morphological and genetic differentiation between two species of the Andean genus Schizanthus that differ in their pollination and mating systems. Schizanthus hookeri has a bee pollination syndrome and is strongly dependent on pollinators for seed set. In contrast, S.?grahamii has a hummingbird pollination syndrome and exhibits late autonomous selfing. Southern populations of the latter species have red flowers (reddish morph), while northern populations have yellow (yellowish morph) or pink flowers (pinkish morph). I used two noncoding chloroplast DNA (cpDNA) regions to investigate the genetic affinities between S.?hookeri and the three morphs of S.?grahamii. I also performed intra- and interspecific crosses to assess whether gene flow between species was possible. Phylogenetic analyses supported the existence of two differentiated clades that did not match currently accepted taxonomic classification. Accordingly, genetic distance did not correlate significantly with morphological distance. No fruits were produced from interspecific crosses, and there were no individuals with intermediate morphology that could indicate current and frequent hybridization events between species.?I propose that the discordance between cpDNA data and conventional taxonomy could be explained by parallel evolution, or alternatively, by a very sporadic hybridization.     

Angiotensin‐Converting Enzyme Gene Polymorphisms and Obesity: An Examination of Three Black Populations

We examined the association between obesity and 13 angiotensin‐converting enzyme (ACE) gene polymorphisms, including the presence (I) or absence (D) of an Alu element in intron 16 (I/D polymorphism), and performed haplotype analysis using data collected from participants of a community survey of hypertension among blacks living in Ibadan, Nigeria; Spanish Town, Jamaica; and Chicago, IL. Transmission distortion of ACE gene polymorphisms and haplotypes from heterozygous parents to affected offspring was examined in each study population. To estimate haplotypes, polymorphisms were divided into three groups based on their position on the ACE gene. No ACE gene polymorphism was consistently overtransmitted from parents to obese offspring among the three populations. However, the haplotype ACE1‐ACE5 TACAT, located in the promoter region, was significantly overtransmitted from parents to obese offspring in both the U.S. and Nigerian populations. No haplotype was significantly overtransmitted from parents to obese offspring among the Jamaicans. In conclusion, we noted the overtransmission of a particular ACE gene promoter region haplotype from parents to obese offspring in two separate black populations. These data suggest that ACE gene polymorphisms may influence the development of weight gain.     

The Taxonomy and Phylogeny of Echinometra (Camarodonta: Echinometridae) from the Red Sea and Western Indian Ocean

The number of valid species in the genus Echinometra (Echinodermata, Echinoidea) and their associated identification keys have been debated in the scientific literature for more than 180 years. As the phylogeny and dispersal patterns of these species have been widely used as a prominent model for marine speciation, new insights into their taxonomy have the potential to deepen our understanding of marine speciation processes. In this study we examine Echinometra taxonomy, combining morphology and molecular tools. We present the taxonomy and phylogeny of Red Sea and Western Indian Ocean Echinometra. The currently available morphological keys were found to be limited in their ability to delineate all species within this genus. Nonetheless, morphological similarities between the Red Sea and Western Indian Ocean populations were high, and delimited them from the other species. These latter populations together formed a monophyletic clade, genetically distant from any of the other Echinometra species by more than 3%. Combining both traditional taxonomy and molecular evidence, we found that these populations were neither Echinometra mathaei nor E. oblonga, as previously considered. The morphological discrepancies of these populations, and their genetic divergence from the other Echinometra species, suggest that they should be considered as a new Echinometra species.     

Clash of the titans: a multi-species invasion with high gene flow in the globally invasive titan acorn barnacle

The goal of this study was to investigate the phylogeny, invasion history and genetic structure of the global invader Megabalanus coccopoma. First, we created a Bayesian phylogeny using cytochrome oxidase I and 16S mitochondrial genes of samples we collected and sequences available on GenBank for all species in the genus Megabalanus. Second, we compared the genetic differences within and between native and invasive populations verified as M. coccopoma by constructing a haplotype network of the COI sequences and estimating gene diversity (h) and nucleotide diversity (π). Finally, we ran an analysis of molecular variance and calculated pairwise Φ _ST to evaluate the similarity among populations. We identified several lineages that correspond to putatively different species of Megabalanus and uncovered nomenclature discrepancies among GenBank samples and undocumented lineages from our own collections. However, we found that the majority of samples were indeed M. coccopoma. Among populations of M. coccopoma, levels of within-population genetic diversity were not significantly different (p _h  = 0.131, p _π  = 0.129) between native (h = 0.970, π = 0.00708) and non-native populations (h = 0.950, π = 0.00605) and analysis of molecular variance analyses revealed that 98.34 % of the genetic variation was partitioned within populations with a significant global Φ _ST  = 0.017. Our results revealed that invasions in at least the southeastern United States and Brazil are composed of multiple lineages; however, we found that most of the global invasion occurred from a single lineage, M. coccopoma, and that no significant genetic differentiation exists between native and non-native populations of this species.     

Idiosyncratic soil-tree species associations and their relationships with drought in a monodominant Amazon forest

Monodominant forests are characterized by the strong influence of a single species on the structure and diversity of the community. In the tropics, monodominant forests are rare exceptions within the generally highly diverse tropical forest biome. Some studies have shown that tree monodominance may be a transient state caused by successional and demographic variation among species over time. Working in a Brosimum rubescens Taub. (Moraceae) monodominant forest at the southern edge of Amazonia, we tested the hypotheses that local-scale variation in intra- and interspecific spatial patterns of dominant tree species is affected by i) demographic rates of recruitment and mortality following severe droughts, ii) local variation in edaphic properties, and iii) occupation of species in the vertical layer of the forest. We quantified intra- and interspecific spatial patterns and edaphic associations of the five most abundant species using aggregation and association distance indices, and examined changes over time. We found some support for all hypotheses. Thus, intra- and interspecific spatial patterns of most species varied over time, principally after severe drought, emphasizing species-level variability and their interactions in sensitivity to this disturbance, even as B. rubescens monodominance was maintained. While positive and negative spatial associations with edaphic properties provide evidence of habitat specialization, the absence of negative spatial associations of B. rubescens with edaphic properties indicates that this species experiences little environmental restriction, and this may be one of the factors that explain its monodominance. Spatial repulsion and attraction between species in the same and in different vertical layers, respectively, indicates niche overlap and differentiation, while changes over time indicate that the relationships between species are dynamic and affected by drought disturbance.     

Phylogenetic relationship in Fritillaria spp. of Iran inferred from ribosomal ITS and chloroplast trnL-trnF sequence data

The genus Fritillaria embraces up to 165 taxa in the family Liliaceae, most of which are of high medicinal and ornamental value and importance. In this study, 44 specimens of the genus representing 9 species were collected from their natural habitats located in 10 provinces of Iran. Phylogenetic analysis was performed based on DNA sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal cistron and the trnL-trnF regions. The phylogeny was constructed using the neighbor joining inference method. Results indicate that the examined samples were evidently diverged into 2 distinct clades. Members of the subgenera Fritillaria and Rhinopetalum formed one clade while the other clade contained the subgenera Theresia and Petilium. There can be seen a high degree of similarity between the only yellow-colored crown imperial specimen and the red-colored specimens. The endemic species of Fritillaria straussii, Fritillaria zagrica and Fritillaria kotschyana which their status within the subgenera known in the genus Fritillaria has been remained undefined, fell into the subgenus Fritillaria. The clades also had relatively reasonable distribution patterns based on the genetic structure, geographical conditions and climate specifications. This study revealed the feasibility of the ITS and trnL-trnF DNA sequence for phylogeny of the genus Fritillaria. This is the first phylogenetic analysis of Fritillaria spp. in Iran.     

New contributions to the taxonomy of urostylid ciliates (Ciliophora,Hypotrichia), with establishment of a new genus and new species

Hypotrichia, one of the most complex and highly differentiated groups in Ciliophora, has been the object of extensive studies, especially in recent years. Nevertheless, methodological difficulties and insufficient faunistic studies have limited our understanding of their biodiversity and phylogeny. In this study, one novel urostylid ciliate, Pseudoholosticha zhaoi nov. gen., nov. spec. and two populations of Anteholosticha monilata (Kahl, 1928) Berger, 2003, type species of the latter genus, are studied using an integrative approach (live observation, protargol impregnation, scanning electron microscopy, and phylogenetic analysis) to provide further insights into the diversity, classification, and phylogeny of this group of ciliates. Pseudoholosticha nov. gen. can be separated from other morphologically similar genera mainly by the absence of buccal and caudal cirri. A key to 12 morphologically similar genera and illustrations of their cirral patterns are provided. The validation of the new genus and new species is supported by both morphological and phylogenetic analyses. The first 18S rRNA gene sequence of A. monilata, with detailed morphological data, provided a reliable clarification of A. monilata populations and corroborated the phylogenetic position of the type species of the polyphyletic genus Anteholosticha.     

Heavy metal resistant strains are widespread along Streptomyces phylogeny

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavy metals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavy metal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavy metals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavy metals originated several times and by different mechanisms in Streptomyces history.     

Microbial Population Analysis of the Salivary Glands of Ticks; A Possible Strategy for the Surveillance of Bacterial Pathogens

Ticks are one of the most important blood-sucking vectors for infectious microorganisms in humans and animals. When feeding they inject saliva, containing microbes, into the host to facilitate the uptake of blood. An understanding of the microbial populations within their salivary glands would provide a valuable insight when evaluating the vectorial capacity of ticks. Three tick species (Ixodes ovatus, I. persulcatus and Haemaphysalis flava) were collected in Shizuoka Prefecture of Japan between 2008 and 2011. Each tick was dissected and the salivary glands removed. Bacterial communities in each salivary gland were characterized by 16S amplicon pyrosequencing using a 454 GS-Junior Next Generation Sequencer. The Ribosomal Database Project (RDP) Classifier was used to classify sequence reads at the genus level. The composition of the microbial populations of each tick species were assessed by principal component analysis (PCA) using the Metagenomics RAST (MG-RAST) metagenomic analysis tool. Rickettsia-specific PCR was used for the characterization of rickettsial species. Almost full length of 16S rDNA was amplified in order to characterize unclassified bacterial sequences obtained in I. persulcatus female samples. The numbers of bacterial genera identified for the tick species were 71 (I. ovatus), 127 (I. persulcatus) and 59 (H. flava). Eighteen bacterial genera were commonly detected in all tick species. The predominant bacterial genus observed in all tick species was Coxiella. Spiroplasma was detected in Ixodes, and not in H. flava. PCA revealed that microbial populations in tick salivary glands were different between tick species, indicating that host specificities may play an important role in determining the microbial complement. Four female I. persulcatus samples contained a high abundance of several sequences belonging to Alphaproteobacteria symbionts. This study revealed the microbial populations within the salivary glands of three species of ticks, and the results will contribute to the knowledge and prediction of emerging tick-borne diseases.     

PLC1 and H2O2 Mediated the Allelopathic Effect of Oridonin on Root Growth in Arabidopsis thaliana

Oridonin is a diterpenoid isolated from medicinal herb Rabdosia rubescens (Hemsl.) Hara (Lamiaceae), which has an allelopathic effect on plants. Phospholipase C (PLC1) and hydrogen peroxide (H₂O₂) are involved in many biotic or abiotic stress responses. Using the 16-day-old seedlings of Arabidopsis thaliana ecotype (WT) and PLC1-deficient mutant (plc1) as materials (treated with 10 μM or 60 μM oridonin for 72 h), the effect of oridonin on root growth regulating by PLC1 and H₂O₂ was investigated. The results showed that the promoting of root growth was about 6.9% at 10 μmol L^?1 oridonin and the inhibiting of root growth was about 19.73% at 60 μmol L^?1 oridonin in WT, the inhibiting of root growth was about 10.5% and 41.2% at 10 mol L^?1 and 60 mol L^?1 oridonin, respectively, in plc1. The expression of ARR1, ARR12, and AHK3 was promoted at low concentrations of oridonin and inhibited at high concentrations in WT, whereas the expression of ARR1 and ARR12 was inhibited with the increase of oridonin concentration in plc1. This suggested that PLC1 was involved in the root growth regulation of oridonin. H₂O₂ was promoted by oridonin with concentration dependence pattern in root cells. Oridonin increased the activity of antioxidant enzymes in both WT and plc1, but the activity of antioxidant enzymes in plc1 was lower than WT. This indicated that PLC1 involved in the activation of antioxidant enzymes promoted by the oridonin. Exogenous CaCl₂ facilitated the accumulation of H₂O₂ in both WT and plc1. And the H₂O₂ of WT was obviously higher than that of plc1. The root growth of WT was inhibited by CaCl₂ with the increase of oridonin. However, there is no effect of CaCl₂ on the root growth in plc1. This reflected that PLC1 positively involved in the regulation of Ca²⁺ on the H₂O₂ and the inhibition effect of Ca²⁺ on the root growth under oridonin treatment. PA promoted the H₂O₂ and suppressed the root growth under oridonin treatment in both WT and plc1. In plc1, PA facilitated the root growth with no oridonin and inhibited the root growth with the increase of oridonin. This reflected that PLC1 positively regulated the promotion effect of PA on the root growth under high oridonin treatment. PLC1 mediated oridonin (10 and 60 mol L^?1) to regulate H₂O₂ levels in A. thaliana seedlings, thereby regulating root tip cell morphology and mitosis. These results demonstrated that PLC1 mediated the low-promotion and high-inhibition effect of oridonin on the root growth in A. thaliana by regulating the concentrations of Ca²⁺ and PA, and further affecting the intracellular H₂O₂ level.

     

The Consequences of Internal Waves for Phytoplankton Focusing on the Distribution and Production of Planktothrix rubescens

Consequences of internal wave motion for phytoplankton and in particular for the distribution and production of the harmful and buoyant cyanobacterium Planktothrix rubescens were investigated based on data from two field campaigns conducted in Lake Ammer during summer 2009 and 2011. In both years, P. rubescens dominated the phytoplankton community and formed a deep chlorophyll maximum (DCM) in the metalimnion. Internal wave motions caused vertical displacement of P. rubescens of up to 6 m and 10 m, respectively. Vertical displacements of isotherms and of iso-concentration lines of P. rubescens from the same depth range coincided, suggesting that P. rubescens did not or could not regulate its buoyancy to prevent wave-induced vertical displacements. Diatoms dominated the phytoplankton community in the epilimnion and were vertically separated from P. rubescens. The thickness of the diatom layer, but not the diatom concentrations within the layer, changed in phase with the changes in the thickness of the epilimnion caused by internal wave motions. Seiche induced vertical displacements of P. rubescens caused fluctuations in the light intensity available at the depth of the P. rubescens layer. The interplay between seiche induced vertical displacements of the P. rubescens layer and the daily cycle of incident light lead to differences in the daily mean available light intensity between lake ends by up to a factor of ∼3. As a consequence, the daily mean specific oxygen production rate of P. rubescens differed by up to a factor of ∼7 between lake ends. The horizontal differences in the specific oxygen production rate of P. rubescens were persistent over several days suggesting that the associated production of P. rubescens biomass may lead to phytoplankton patchiness. The effect of internal seiches on the spatial heterogeneity and the persistence of horizontal differences in production, however, depend on the timing and the synchronization between internal wave motion and the daily course of incident light intensity. Vertical displacements caused by internal waves could be distinguished from other factors influencing the distribution of P. rubescens (e.g. active buoyancy control, production, vertical mixing) by a temperature-based data transformation. This technique may be of general use for separating wave-induced transport from other processes (e.g. sedimentation, vertical mixing) that affect the distributions of dissolved substances and suspended particles.