Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves

Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites) in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL) is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC) corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC) presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate change-induced sea level rise

Pneumothorax after computed tomography-guided lung biopsy: Utility of immediate post-procedure computed tomography and one-hour delayed chest radiography

Purpose To evaluate the utility of immediate post-procedure computed tomography (IPP-CT) and routine one-hour chest radiography (1HR-CXR) for detecting and managing pneumothorax in patients undergoing computed tomography (CT)-guided percutaneous lung biopsy. Materials and methods All CT-guided percutaneous lung biopsies performed between May 2014 and August 2021 at a single institution were included. Data from 275 procedures performed on 267 patients (147 men; mean age: 63.5 ± 14.1 years; range 18–91 years) who underwent routine 1HR-CXR were reviewed. Incidences of pneumothorax and procedure-related complications on IPP-CT and 1HR-CXR were recorded. Associated variables, including tract embolization methods, needle diameter/type, access site, lesion size, needle tract distance, and number of biopsy samples obtained were analyzed and compared between groups with and without pneumothorax. Results Post-procedure complications included pneumothorax (30.9%, 85/275) and hemoptysis (0.7%, 2/275). Pneumothorax was detected on IPP-CT and 1HR-CXR in 89.4% (76/85) and 100% (85/85), respectively. A chest tube was placed in 4% (11/275) of the cases. In 3.3% (9/275) of the cases, delayed pneumothorax was detected only on 1HR-CXR, but no patient in this group necessitated chest tube placement. The incidence of pneumothorax was not significantly different between tract embolization methods (p = 0.36), needle diameters (p = 0.36) and types (p = 0.33), access sites (p = 0.07), and lesion sizes (p = 0.88). On logistic regression, a lower biopsy sample number (OR = 0.49) was a protective factor, but a longer needle tract distance (OR = 1.16) was a significant risk factor for pneumothorax. Conclusion Following CT-guided percutaneous lung biopsy, pneumothorax detected on IPP-CT strongly indicates persistent pneumothorax on 1HR-CXR and possible chest tube placement. If no pneumothorax is identified on IPP-CT, follow-up 1HR-CXR may be required only for those who develop symptoms of pneumothorax

Broadening Participation in Biology Education Research: Engaging Community College Students and Faculty

Nearly half of all undergraduates are enrolled at community colleges (CCs), including the majority of U.S. students who represent groups underserved in the sciences. Yet only a small minority of studies published in discipline-based education research journals address CC biology students, faculty, courses, or authors. This marked underrepresentation of CC biology education research (BER) limits the availability of evidence that could be used to increase CC student success in biology programs. To address this issue, a diverse group of stakeholders convened at the Building Capacity for Biology Education Research at Community Colleges meeting to discuss how to increase the prevalence of CC BER and foster participation of CC faculty as BER collaborators and authors. The group identified characteristics of CCs that make them excellent environments for studying biology teaching and learning, including student diversity and institutional cultures that prioritize teaching, learning, and assessment. The group also identified constraints likely to impede BER at CCs: limited time, resources, support, and incentives, as well as misalignment between doing research and CC faculty identities as teachers. The meeting culminated with proposing strategies for faculty, administrators, journal editors, scientific societies, and funding agencies to better support CC BER

Biochemical and bioactive phytonutrients changes in tissues of two cultivars of fresh-cut cassava in stick form under refrigerated storage

The aim of this study was to evaluate the effects of fresh-cut in stick form of two cassava cultivars on their biochemical and antioxidant characteristics, at two harvest times. The fresh cut cassava sticks were packaged in polypropylene, maintained at 5±1ºC, with 90±5% relative humidity for 12 days. The concentration of carotenoids, total soluble phenolic compounds and the activity of phenylalanine ammonia lyase and antioxidant capacity were significantly higher for the sticks of cultivar 'Amarela' cassava than for the sticks of cultivar 'Cacau'. The concentrations of carotenoids, total soluble phenolic compounds, and the activity of phenylalanine ammonia lyase and antioxidant capacity were all significantly greater when harvested at 14-month of age. There was a significant increase in the activity of phenylalanine ammonia lyase during the 12 days of storage at 5ºC. However, there was a decrease in total carotenoids, soluble phenolic compounds, and in the antioxidant capacity of the two cultivars

Challenges of biotechnology and genetically modified crops for food security in a developing economy

No Abstract.Journal of the Cameroon Academy of Sciences Vol. 6 (1) 2006: pp 9-1

Agronomic performances, yield stability and field disease reaction of cassava genotypes in the sub-humid forest region of Cameroon

(African Crop Science Journal: 1999 7(2): 129-142

Effets de la mycorhize à vésicules et arbuscules, de la température et du phosphore sur la fusariose de la patate douce

Réunion: International Society for Tropical Root Crops. Africa Branch, Triennial Symposium, 2d, 14-19 Aug. 1983, Douala, CMDans IDL-638

Reaction of cassava genotypes to the cassava mosaic disease in three distinct agroecologies in Nigeria

Nine cassava genotypes were grown at six representative sites in Nigeria for 3 years to study their response to cassava mosaic disease (CMD), investigate the influence of genotype × environment (G× E) interactions on their reactions to the disease, and identify genotypes with stability to the disease, using the Additive Main Effects and Multiplicative Interaction statistical model. Environments, genotypes and G × E interactions were highly significant (P < 0.01) for the disease. The G × E interactions accounted for 19.5% of the treatment sums of squares for CMD and influenced the relative ranking of genotypes across environments. The magnitude of the G × E interaction effect for CMD was larger than that of genotypes. Examination of the G × E interaction structure revealed specific areas where screening of cassava genotypes for resistance to CMD could be performed best. The study identified genotypes such as TMS 30001 and 63397 with resistance to CMD and CMD‐stable clone U/41044, which could be distributed to growers, and sites such as Ibadan and Ubiaja with high CMD severity for screening genotypes for reaction to CMD