Flora of Cameroon - Annonaceae Vol 45.

Annonaceae is a major pantropical family with 113 genera and about 2550 species. Cameroon is one of the most biodiverse countries in Africa but its flora remains incompletely known. In this volume of the Flora of Cameroon, we describe 166 native taxa representing 163 species in 28 native genera within the family Annonaceae.

A risk assessment review of mercury exposure in Arctic marine and terrestrial mammals.

There has been a considerable number of reports on Hg concentrations in Arctic mammals since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to mercury (Hg) in Arctic biota in 2010 and 2018. Here, we provide an update on the state of the knowledge of health risk associated with Hg concentrations in Arctic marine and terrestrial mammal species. Using available population-specific data post-2000, our ultimate goal is to provide an updated evidence-based estimate of the risk for adverse health effects from Hg exposure in Arctic mammal species at the individual and population level.

A freshwater mesocosm study into the effects of the neonicotinoid insecticide thiamethoxam at multiple trophic levels.

Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of insect pests. To assess potential risks from this compound to non-target aquatic organisms, an outdoor mesocosm study was performed. Mesocosms (1300 L) were treated once with a formulated product with the active substance (a.

Floral evolution by simplification in Monanthotaxis (Annonaceae) and hypotheses for pollination system shifts.

Simplification by reduction has occurred many times independently in the floral evolution of angiosperms. These reductions have often been attributed to changes in reproductive biology. In the angiosperm plant family Annonaceae, most species have flowers with six petals, and many stamens and carpels.

Response of the mayfly (Cloeon dipterum) to chronic exposure to thiamethoxam in outdoor mesocosms.

Thiamethoxam is a widely used neonicotinoid insecticide that has been detected in surface water monitoring programs in North America and Europe. This has led to questions about its toxicity to nontarget insects, specifically those with an aquatic life stage. To address the uncertainty associated with possible impacts from environmental exposures, a chronic (35-d) outdoor mesocosm study with a formulated product containing thiamethoxam was conducted.

Correlated evolutionary rates across genomic compartments in Annonaceae.

The molecular clock hypothesis is an important concept in biology. Deviations from a constant rate of nucleotide substitution have been found widely among lineages, genomes, genes and individual sites. Phylogenetic research can accommodate for these differences in applying specific models of evolution.

Comprehensive characterization of the acute and chronic toxicity of the neonicotinoid insecticide thiamethoxam to a suite of aquatic primary producers, invertebrates, and fish.

Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of chewing and sucking insect pests. Recent detection of thiamethoxam in surface waters has raised interest in characterizing the potential impacts of this insecticide to aquatic organisms. We report the results of toxicity testing (acute and chronic) conducted under good laboratory practices for more than 30 freshwater species (insects, molluscs, crustaceans, algae, macrophytes, and fish) and 4 marine species (an alga, a mollusc, a crustacean, and a fish).

A nonet of novel species of (Annonaceae) from around Africa.

As part of an ongoing revision of the genus Baill. (Annonaceae), nine new species are described and one variety is reinstated to species rank. Two new species from West Africa ( P.

Integrating omic technologies into aquatic ecological risk assessment and environmental monitoring: hurdles, achievements, and future outlook.

Background: In this commentary we present the findings from an international consortium on fish toxicogenomics sponsored by the U.K. Natural Environment Research Council (Fish Toxicogenomics-Moving into Regulation and Monitoring, held 21-23 April 2008 at the Pacific Environmental Science Centre, Vancouver, BC, Canada).

Vitamin A and E tissue distribution with comparisons to organochlorine concentrations in the serum, blubber and liver of the bowhead whale (Balaena mysticetus).

Vitamin A and E concentrations were determined in liver (n=51), blubber (n=23) and serum (n=53) of subsistence-hunted bowhead whales (Balaena mysticetus), between 1998 and 2001. Retinol and alpha-tocopherol were the major forms of vitamins A and E detected, respectively. Liver contained the highest mean concentrations of vitamin A, followed by epidermis, blubber, and serum.

Estrogenic activity of dicofol with the human estrogen receptor: Isomer- and enantiomer-specific implications.

Dicofol is a non-systemic acaricide/miticide currently registered in the US and Canada for use on a wide variety of crops. This agrochemical has been identified as a potential candidate substance for the United Nations Economic Commission for Europe (UN-ECE) Persistent Organic Pollutant (POP) Protocol and implicated as a potential "endocrine disrupting compound". The technical product is usually synthesized from technical DDT and consists of approximately 80% and 20% of p,p'- and o,p'-dicofol isomers.

Concentrations of selected persistent organochlorine contaminants in store-bought foods from northern Alaska.

Objectives: We address marine and terrestrial mammal blubber, liver, muscle, kidney, heart, tongue, maktak and maktaaq (epidermis and blubber from bowhead, beluga whales, respectively), and fish muscle and livers, as commonly consumed tissues in subsistence communities across northern Alaska in the context of organochlorine (OC) contamination of store-bought foods. Human exposure to contaminants from biota, as part of a subsistence diet, has been superficially evaluated in numerous studies (focused on liver and blubber), but are limited in the type of tissues analyzed, and rarely consider the contaminants in the alternatives (i.e.

Spatial and temporal trends of contaminants in terrestrial biota from the Canadian Arctic.

Contaminants in the Canadian Arctic have been studied over the last twelve years under the guidance of the Northern Contaminants Program. This paper summarizes results from that program from 1998 to 2003 with respect to terrestrial animals in the Canadian Arctic. The arctic terrestrial environment has few significant contaminant issues, particularly when compared with freshwater and marine environments.

Development and application of bioaccumulation models to assess persistent organic pollutant temporal trends in arctic ringed seal (Phoca hispida) populations.

Individual- and population-based models were developed to simulate the bioaccumulation of persistent organic pollutants (POPs) over the lifetime of ringed seals (Phoca hispida) and account for the effects of age, growth, body condition and sex (including gestation, birth and lactation). Lactational transfer was described using a milk to blubber partition coefficient, which was shown to be a function of Kow (KMB=1/(1.676+1.

Bioaccumulation factors for PCBs revisited.

Bioaccumulation factors (BAFs) for individual polychlorinated biphenyl (PCB) congeners in Barents Sea and White Sea marine calanoid copepods were 1-3 orders of magnitude higher than BAFs in the same species in Canadian and Alaskan Arctic Ocean areas, and in freshwater plankton (Lake Ontario) reported from the mid- to early 1980s. The present study reviews variability in PCB BAFs from the North American Great Lakes and the Arctic Ocean, and discusses possible explanations for the large variation among different studies. BAFs are higher in recent arctic marine and Great Lakes studies than previously reported, and they are at least 10 times higher than those predicted from the octanol-water partition coefficient (KOW).

Organohalogen contaminants in delphinoid cetaceans.

This chapter reviews the global distribution, biotransformation, accumulation patterns, and mechanisms of action and the potential impacts of persistent organohalogen contaminants (PHCs) on physiological systems of cetaceans with emphasis on delphinoids. Methods used to study PHCs in stranded and free-living cetaceans are discussed, and concentrations of PHCs of stranded, hunted, by-catch, and free-ranging delphinoids are summarized. Overall, the highest concentrations of PHC contamination were found in delphinoids from industrialized areas of the Northern Hemisphere compared to the Southern Hemisphere.

Biological and chemical factors of importance in the bioaccumulation and trophic transfer of persistent organochlorine contaminants in Arctic marine food webs.

Recent studies of arctic marine food webs have provided detailed insights regarding the biological and chemical factors that influence the bioaccumulation and trophic transfer of persistent organochlorine (OC) contaminants in aquatic systems. The present paper summarizes the recent literature with an emphasis on identifying important ecological factors for explaining variability of OC concentrations among organisms. The Arctic ecosystem has a number of unique attributes, including long food chains, reduced diversity of species, similar food webs across the entire region, and limited influence from pollution point sources.

Toxicokinetics of three polychlorinated biphenyl technical mixtures in rainbow trout (Oncorhynchus mykiss).

Accumulation and depuration parameters of polychlorinated biphenyls (PCBs) in fish have been reported only for a few congeners. As well, there is little information on the ability of fish to biotransform PCBs. To address these issues, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to dietary concentrations of three Aroclor mixtures (1248, 1254, 1260) in food for 30 d followed by an additional 160 d of nonspiked food at 8 degrees C.

Identification of long-chain perfluorinated acids in biota from the Canadian Arctic.

Recently it was discovered that humans and animals from various urban and remote global locations contained a novel class of persistent fluorinated contaminants, the most pervasive of which was perfluorooctane sulfonate (PFOS). Lower concentrations of perfluorooctanoate, perfluorohexane sulfonate, and heptadecafluorooctane sulfonamide have also been detected in various samples. Although longer perfluoroalkyl carboxylates (PFCAs) are used in industry and have been detected in fish following a spill of aqueous film forming foam, no studies have been conducted to examine the widespread occurrence of long-chain PFCAs (e.

Hydroxylated and methylsulfone-containing metabolites of polychlorinated biphenyls in the plasma and blubber of bowhead whales (Balaena mysticetus).

Bowhead whale (Balaena mysticetus) blubber (n = 20) and plasma (n = 19) samples were collected during the 1997 to 2000 Inuit subsistence harvests in Barrow, Alaska, USA, to quantify the concentrations of methylsulfone (MeSO2)-containing and hydroxylated (OH) polychlorinated biphenyl (PCB) metabolites in this cetacean. The distribution of MeSO2-PCBs in blubber was dominated by 4-MeSO2-substituted congeners, the most abundant being 4-MeSO2-CB-70, 3'-MeSO2-CB-132, and 4-MeSO2-CB-64. Mean (+/- 1 standard error) sum (sigma) MeSO2-PCBs concentrations in blubber were low (6.

Enantiomer-specific biomagnification of alpha-hexachlorocyclohexane and selected chiral chlordane-related compounds within an Arctic marine food web.

Concentrations of achiral and chiral organochlorine contaminants (OCs), including hexachlorocyclohexane isomers (HCH), chlordane congeners (cis- and trans-chlordane, cis- and trans-nonachlor, MC5, MC7, and U82), and related metabolites (oxychlordane [OXY] and heptachlor exo-epoxide [HEPX]), were quantified in seawater (100 L; n = 6) and biota from the coastal Beaufort-Chukchi Seas food web near Barrow (AK, USA). The biota included zooplankton (Calanus spp.; n = 5), fish species such as arctic cod (Boreogadus saida; n = 10), arctic char (Salvelinus alpinus; n = 3), and marine mammals including bowhead whales (Balaena mysticetus; liver: n = 23; blubber: n = 40), beluga whales (Delphinapterus leucas; blubber: n = 20), ringed seals (Phoca hispida; blubber: n = 20), and bearded seals (Erignathus barbatus; blubber: n = 7).

Enantiomer fractions of chiral organochlorine pesticides and polychlorinated biphenyls in standard and certified reference materials.

Enantiomeric ratios (ERs) and enantiomeric fractions (EFs) of a number of chiral organochlorine pesticides and PCB atropisomers were measured by chiral gas chromatography/mass spectrometry (GC/MS) in five standard (SRM) and certified (CRM) reference materials: SRM 1588a (organics in cod liver oil), SRM 1945 (organics in whale blubber), Marine Mammal Quality Assurance Exercise Control Material IV (NIST IV, organics in whale blubber), CRM trout, and CRM EC-5 (sediment). Target analytes were cis- and trans-chlordane, heptachlor exo-epoxide, oxychlordane, U82, MC5, MC6, MC7, o,p'-DDT, and PCB congeners 91, 95, 136, 149, 174, 176, and 183. Measured ERs and EFs are in close agreement with the few literature values reported for some of these analytes in SRMs and CRMs.

Enantiomer-specific accumulation of PCB atropisomers in the bowhead whale (Balaena mysticetus).

Blubber (n = 40) and liver (n = 20) samples from the bowhead whale (Balaena mysticetus) were collected during the 1997-1998 Native (Inuit) subsistence harvests in Barrow, AK. Bowhead tissues and zooplankton were analyzed for polychlorinated biphenyl (PCB) concentrations and the enantiomeric fractions (EFs) of eight chiral PCB congeners (PCB-91, 95, 135, 136, 149, 174, 176, and 183) to quantify the enantiomer-specific accumulation of PCBs in this cetacean. PCB concentrations in bowhead blubber were low (mean +/- 1 SE: 610 +/- 54 ng g(-1) lipid) relative to other cetaceans.

Spatial trends and bioaccumulation of organochlorine pollutants in marine zooplankton from the Alaskan and Canadian Arctic.

Planktonic copepods (Calanus glacialis and C. hyperboreus; n = 37) and water (n = 19) were collected to examine the spatial distribution and bioaccumulation of organochlorine contaminants (OCs) in the Alaskan and Canadian Arctic. The rank order of total OC (sigma OC) group concentrations in Calanus samples was toxaphene > or = sigma polychlorinated biphenyls (PCBs) > sigma hexachlorcyclohexane (HCH) > sigma DDT > sigma chlordane-related compounds (CHLOR) > sigma chlorobenzenes (ClBz).