Association of Meteorological Factors With COVID-19 During Harmattan in Nigeria.

Harmattan is a season of dry, cold, dusty wind, and haze that is peculiar to West Africa. This season and COVID-19 share common conditions such as malaise and respiratory issues like as runny nose, cough and sneezing, and raise a question of a possible relationship that begs to be answered. This study investigated whether the meteorological factors of humidity and wind speed during harmattan have association with COVID-19 incidence and mortality in the 2 major COVID-19 epicenters of Lagos state and the Federal Capital Territory (FCT) in southern and northern geopolitical regions of Nigeria respectively. Data used were from March, 2020 to February, 2022, which corresponded to the period of 2 years after the first case of COVID-19 was detected in Nigeria. Correlation analysis was performed using incidence or mortality data on COVID-19 over the duration of 2 years and during the harmattan periods, as well as the humidity and wind speed data for the corresponding periods. Our results showed that there was no significant correlation between the humidity or wind speed and COVID-19 daily incidence or mortality during the harmattan and non-harmattan periods in Lagos state. In the FCT however, there was a significant positive correlation between humidity and COVID-19 incidence, as well as a negative correlation between wind speed and COVID-19 incidence. No significant correlation existed between humidity or wind speed and daily mortality. Taken together, the findings of this study show that weather components of the harmattan season have association with COVID-19 incidence but not mortality, and the association could vary depending on location.

Therapeutic and Vaccine Options for COVID-19: Status after Six Months of the Disease Outbreak.

An outbreak of the coronavirus disease 2019 (COVID-19) caused by an infection of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred in Wuhan, China, in December 2019. This new virus belongs to the group of enveloped RNA beta-coronaviruses. Symptoms may differ in various infected persons, but major presentations include dry cough, nasal congestion, shortness of breath, fever, and general malaise. The disease appears to be more severe in patients above the age of 60 years and those with underlying conditions such as diabetes, cancer, cardiovascular diseases, chronic respiratory disease, and hypertension. There is still no approved vaccine against COVID-19, but more than a hundred are at different stages of development. It is known that the development of new drugs takes a relatively long time, so several known and already-approved drugs are being repurposed for the treatment of this disease. In this review, we explore the therapeutic and vaccine options that are available for COVID-19 6 months after its outbreak. Most noteworthy among the therapeutic options are dexamethasone, remdesivir, Avigan (favipiravir) and convalescent plasma.

Next-generation gene drive for population modification of the malaria vector mosquito, Anopheles gambiae.

A Cas9/guide RNA-based gene drive strain, AgNosCd-1, was developed to deliver antiparasite effector molecules to the malaria vector mosquito, Anopheles gambiae The drive system targets the cardinal gene ortholog producing a red-eye phenotype. Drive can achieve 98 to 100% in both sexes and full introduction was observed in small cage trials within 6 to 10 generations following a single release of gene-drive males. No genetic load resulting from the integrated transgenes impaired drive performance in the trials. Potential drive-resistant target-site alleles arise at a frequency <0.1, and five of the most prevalent polymorphisms in the guide RNA target site in collections of colonized and wild-derived African mosquitoes do not prevent cleavage in vitro by the Cas9/guide RNA complex. Only one predicted off-target site is cleavable in vitro, with negligible deletions observed in vivo. AgNosCd-1 meets key performance criteria of a target product profile and can be a valuable component of a field-ready strain for mosquito population modification to control malaria transmission.

Effect of Weather on COVID-19 Transmission and Mortality in Lagos, Nigeria.

The novel coronavirus disease 2019 (COVID-19) has become a global pandemic with more than 4 million confirmed cases and over 280,000 confirmed deaths worldwide. Evidence exists on the influence of temperature and humidity on the transmission of related infectious respiratory diseases, such as influenza and severe acute respiratory syndrome (SARS). This study therefore explored the effects of daily temperature and humidity on COVID-19 transmission and mortality in Lagos state, the epicenter of COVID-19 in Nigeria. Correlation analysis was performed using incidence data on COVID-19 and meteorological data for the corresponding periods from 9th March to 12th May, 2020. Our results showed that atmospheric temperature has a significant weak negative correlation with COVID-19 transmission in Lagos. Also, a significant weak negative correlation was found to exist between temperature and cumulative mortality. The strength of the relationship between temperature and the disease incidence increased when 1 week and 2 weeks' predetection delays were put into consideration. However, no significant association was found between atmospheric humidity and COVID-19 transmission or mortality in Lagos. This study contributes more knowledge on COVID-19 and will benefit efforts and decision-making geared towards its control.

Ribosome Display Technology: Applications in Disease Diagnosis and Control.

Antibody ribosome display remains one of the most successful in vitro selection technologies for antibodies fifteen years after it was developed. The unique possibility of direct generation of whole proteins, particularly single-chain antibody fragments (scFvs), has facilitated the establishment of this technology as one of the foremost antibody production methods. Ribosome display has become a vital tool for efficient and low-cost production of antibodies for diagnostics due to its advantageous ability to screen large libraries and generate binders of high affinity. The remarkable flexibility of this method enables its applicability to various platforms. This review focuses on the applications of ribosome display technology in biomedical and agricultural fields in the generation of recombinant scFvs for disease diagnostics and control.

CRISPR in Sub-Saharan Africa: Applications and Education.

Clustered regularly interspaced short palindromic repeats (CRISPR) technology has enabled genetic engineering feats previously considered impracticable, offering great hopes for solutions to problems facing society. We consider it timely to highlight how CRISPR can benefit public health, medicine, and agriculture in sub-Saharan Africa (SSA) and offer recommendations for successful implementation.

Hyperactive piggyBac transposase improves transformation efficiency in diverse insect species.

Even in times of advanced site-specific genome editing tools, the improvement of DNA transposases is still on high demand in the field of transgenesis: especially in emerging model systems where evaluated integrase landing sites have not yet been created and more importantly in non-model organisms such as agricultural pests and disease vectors, in which reliable sequence information and genome annotations are still pending. In fact, random insertional mutagenesis is essential to identify new genomic locations that are not influenced by position effects and thus can serve as future stable transgene integration sites. In this respect, a hyperactive version of the most widely used piggyBac transposase (PBase) has been engineered. The hyperactive version (hyPBase) is currently available with the original insect codon-based coding sequence (ihyPBase) as well as in a mammalian codon-optimized (mhyPBase) version. Both facilitate significantly higher rates of transposition when expressed in mammalian in vitro and in vivo systems compared to the classical PBase at similar protein levels. Here we demonstrate that the usage of helper plasmids encoding the hyPBase - irrespective of the codon-usage - also strikingly increases the rate of successful germline transformation in the Mediterranean fruit fly (Medfly) Ceratitis capitata, the red flour beetle Tribolium castaneum, and the vinegar fly Drosophila melanogaster. hyPBase-encoding helpers are therefore highly suitable for the generation of transgenic strains of diverse insect orders. Depending on the species, we achieved up to 15-fold higher germline transformation rates compared to PBase and generated hard to obtain transgenic T. castaneum strains that express constructs affecting fitness and viability. Moreover, previously reported high sterility rates supposedly caused by hyPBase (iPB7), encoded by ihyPBase, could not be confirmed by our study. Therefore, we value hyPBase as an effective genetic engineering tool that we highly recommend for insect transgenesis.

Characterization of a Lactococcus lactis promoter for heterologous protein production.

Constitutively active promoter elements for heterologous protein production in Lactococcus lactis are scarce. Here, the promoter of the PTS-IIC gene cluster from L. lactis NZ3900 is described. This promoter was cloned upstream of an enhanced green fluorescent protein, GFPmut3a, and transformed into L. lactis. Transformants produced up to 13.5 µg of GFPmut3a per milliliter of log phase cells. Addition of cellobiose further increased the production of GFPmut3a by up to two-fold when compared to glucose. Analysis of mutations at two specific positions in the PTS-IIC promoter showed that a 'T' to 'G' mutation within the -35 element resulted in constitutive expression in glucose, while a 'C' at nucleotide 7 in the putative cre site enhanced promoter activity in cellobiose. Finally, this PTS-IIC promoter is capable of mediating protein expression in Bacillus subtilis and Escherichia coli Nissle 1917, suggesting the potential for future biotechnological applications of this element and its derivatives.

Towards area-wide control of Bactrocera invadens: prospects of the sterile insect technique and molecular entomology.

It is 10 years since the first detection of the invader fruit fly, Bactrocera invadens, in sub-Saharan Africa. The pest continues to hamper fruit production and create barriers to trade. Strategies currently employed to control B. invadens are insufficient, and more effective area-wide strategies are needed. The sterile insect technique and molecular entomology approaches have high potential and could help to bring about effective area-wide control of the pest if adopted and used as components of area-wide integrated pest management.

Molecular cloning and expression of nanos in the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae).

The gene nanos (nos) is a maternal-effect gene that plays an important role in posterior patterning and germ cell development in early stage embryos. nos is known from several diverse insect species, but has so far not been described for any Tephritid fruit fly. Here, we report the molecular cloning and expression pattern of the nos orthologous gene, Ccnos, in the Mediterranean fruit fly Ceratitis capitata, which is a destructive pest of high agricultural importance. CcNOS contains 398 amino acids and has a C-terminal region with two conserved CCHC zinc-binding motifs known to be essential for NOS function. Transcripts of Ccnos were confirmed by in situ hybridization to be maternally-derived and localized to the posterior pole of early stage embryos. Regulatory regions of nos have been employed in genetic engineering in some dipterans such as Drosophila and mosquitoes. Given the similarity in spatial and temporal expression between Ccnos and nos orthologs from other dipterans, its regulatory regions will be valuable to generate additional genetic tools that can be applied for engineering purposes to improve the fight against this devastating pest.

Transgenic sexing system for Ceratitis capitata (Diptera: Tephritidae) based on female-specific embryonic lethality.

Fruit fly pest species have been successfully controlled and managed via the Sterile Insect Technique (SIT), a control strategy that uses infertile matings of sterile males to wild females to reduce pest populations. Biological efficiency in the field is higher if only sterile males are released in SIT programs and production costs are also reduced. Sexing strains developed in the Mediterranean fruit fly Ceratitis capitata (medfly) through classical genetics are immensely beneficial to medfly SIT programs but exhibit reduced fertility and fitness. Moreover, transfer of such classical genetic systems to other tephritid species is difficult. Transgenic approaches can overcome this limitation of classical genetic sexing strains (GSSs), but had resulted so far in transgenic sexing strains (TSSs) with dominant lethality at late larval and pupal stages. Here we present a transgene-based female-specific lethality system for early embryonic sexing in medfly. The system utilizes the sex-specifically spliced transformer intron to restrict ectopic mRNA translation of the pro-apoptotic gene hid(Ala5) to females only. The expression of this lethal effector gene is driven by a tetracycline-repressible transactivator gene tTA that is under the control of promoters/enhancers of early-acting cellularization genes. Despite observed position effects on the sex-specific splicing, we could effectively establish this early-acting transgenic sexing system in the medfly C. capitata. After satisfactory performance in large scale tests, TSSs based on this system will offer cost-effective sexing once introduced into SIT programs. Moreover, this approach is straight forward to be developed also for other insect pest and vector species.