Variation in diosgenin level in seed kernels among different provenances of Balanites aegyptiaca Del (Zygophyllaceae) and its correlation with oil content

Balanites aegyptiaca (Zygopyllaceae) is a widely grown desert plant with multi-use potential. It is found in most of the African continent, the Middle East, and South Asia; however, this plant remains one of the most neglected plant species. Its seed kernel is used for oil extraction and the oil is used for human consumption and cosmetics. However, the oil cake is regarded as unsuitable for feeding because of the presence of many toxic substances. In this study, a spectrophotometric determination of diosgenin level and subsequent oil percentage analyses were carried out using the seed kernels of B. aegyptiaca collected from five Israeli provenances (Bet-Shean, Ein-gedi, Sapir, Samar, and Eilat) and five international locations (Burkina Faso, Senegal, Mali, Niger, and India). The results suggested that the sample from the Bet Shean Valley, which is considered the northern-most latitude where B. aegyptiaca naturally grows, contained the highest level of diosgenin as well as oil percentage; the Indian sample contained the lowest levels of both diosgenin and oil. The result also showed that there is a strong positive correlation (R2 = 0.849) between diosgenin level and oil percentage in the B. aegyptiaca seed kernel

Larvicidal effects of aqueous extracts of Balanites aegyptiaca (desert date) against the larvae of Culex pipiens mosquitoes

The effect of aqueous extracts of the fruit pulp, seed kernel, roots, bark, and leaves of Balanites aegyptiaca Del. (Zygophyllacea) against the larvae of the Culex pipens mosquito was investigated. Early fourth instars larvae of C. pipiens mosquitoes were exposed, for up to three days, to a dilution of 0, 0.1,0.25, 0.5, 1.0, and 2.0% aqueous extracts of fruit pulp, seed kernel, roots, bark, and leaves. All tested extracts showed larval mortality, however, larval mortality was greatest with the aqueous root extract. The lowest concentration of root extract (0.1%) showed 100% larval mortality after three days, whereasa 0.5% concentration of aqueous bark extract was needed for 100% larval mortality. Aqueous extracts of leaf, fruit pulp, and seed kernel showed less larval mortality compared to the root and/or bark extracts. It is suggested that all parts of the B. aegyptiaca contain larvicidal properties that could bedeveloped and used as natural insecticides for mosquito control

Plasma membrane association facilitates conformational changes in the Marburg virus protein VP40 dimer

Filovirus infections cause hemorrhagic fever in humans and non-human primates that often results in high fatality rates. The Marburg virus is a lipid-enveloped virus from the Filoviridae family and is closely related to the Ebola virus. The viral matrix layer underneath the lipid envelope is formed by the matrix protein VP40 (VP40), which is also involved in other functions during the viral life-cycle. As in the Ebola virus VP40 (eVP40), the recently determined X-ray crystal structure of the Marburg virus VP40 (mVP40) features loops containing cationic residues that form a lipid binding basic patch. However, the mVP40 basic patch is significantly flatter with a more extended surface than in eVP40, suggesting the possibility of differences in the plasma membrane interactions and phospholipid specificity between the VP40 dimers. In this paper, we report on molecular dynamics simulations that investigate the roles of various residues and lipid types in PM association as well as the conformational changes of the mVP40 dimer facilitated by membrane association. We compared the structural changes of the mVP40 dimer with the mVP40 dimer in both lipid free and membrane associated conditions. Despite the significant structural differences in the crystal structure, the Marburg VP40 dimer is found to adopt a configuration very similar to the Ebola VP40 dimer after associating with the membrane. This conformational rearrangement upon lipid binding allows Marburg VP40 to localize and stabilize at the membrane surface in a manner similar to the Ebola VP40 dimer. Consideration of the structural information in its lipid-interacting condition may be important in targeting mVP40 for novel drugs to inhibit viral budding from the plasma membrane

Domain Rearrangement and Denaturation in Ebola Virus Protein VP40

The VP40 protein plays a critical role in coordinating the virion assembly, budding, and replication of the Ebola virus. Efforts have been made in recent years to understand various aspects of VP40 structure, dynamics, and function such as assembly of the protein and its roles in virus replication and penetration of the protein into the plasma membrane. A major conformational transformation is necessary for VP40 to form some of its oligomeric structures and to perform various functions. This conformational change from a compact structure with the N-terminal domain (NTD) and C-terminal domain (CTD) closely associated involves a dissociation or springing-out of the CTD from the NTD. We perform investigations using computational molecular dynamics simulations as well as knowledge-based Monte Carlo simulations. We find that a sharp springing of the CTD from the NTD in a free VP40 protein cannot occur solely by random thermal fluctuations without intermediate oligomerized segments, and therefore is likely triggered by additional molecular events

Structural insights into the repair mechanism of AGT for methyl-induced DNA damage

Methylation induced DNA base-pairing damage is one of the major causes of cancer. O6-alkylguanine-DNA alkyltransferase (AGT) is considered a demethylation agent of the methylated DNA. Structural investigations with thermodynamic properties of the AGT-DNA complex are still lacking. In this report, we modeled two catalytic states of AGT-DNA interactions and an AGT-DNA covalent complex and explored structural features using molecular dynamics (MD) simulations. We utilized the umbrella sampling method to investigate the changes in the free energy of the interactions in two different AGT-DNA catalytic states, one with methylated GUA in DNA and the other with methylated CYS145 in AGT. These non-covalent complexes represent the pre- A nd post-repair complexes. Therefore, our study encompasses the process of recognition, complex formation, and separation of the AGT and the damaged (methylated) DNA base. We believe that the use of parameters for the amino acid and nucleotide modifications and for the protein-DNA covalent bond will allow investigations of the DNA repair mechanism as well as the exploration of cancer therapeutics targeting the AGT-DNA complexes at various functional states as well as explorations via stabilization of the complex

Covalent Complex of DNA and Bacterial Topoisomerase: Implications in Antibacterial Drug Development

A topoisomerase-DNA transient covalent complex can be a druggable target for novel topoisomerase poison inhibitors that represent a new class of antibacterial or anticancer drugs. Herein, we have investigated molecular features of the functionally important Escherichia coli topoisomerase I (EctopoI)-DNA covalent complex (EctopoIcc) for molecular simulations, which is very useful in the development of new antibacterial drugs. To demonstrate the usefulness of our approach, we used a model small molecule (SM), NSC76027, obtained from virtual screening. We examined the direct binding of NSC76027 to EctopoI as well as inhibition of EctopoI relaxation activity of this SM via experimental techniques. We then performed molecular dynamics (MD) simulations to investigate the dynamics and stability of EctopoIcc and EctopoI-NSC76027-DNA ternary complex. Our simulation results show that NSC76027 forms a stable ternary complex with EctopoIcc. EctopoI investigated here also serves as a model system for investigating a complex of topoisomerase and DNA in which DNA is covalently attached to the protein

Graphene-VP40 interactions and potential disruption of the Ebola virus matrix filaments

Ebola virus infections cause hemorrhagic fever that often results in very high fatality rates. In addition to exploring vaccines, development of drugs is also essential for treating the disease and preventing the spread of the infection. The Ebola virus matrix protein VP40 exists in various conformational and oligomeric forms and is a potential pharmacological target for disrupting the virus life-cycle. Here we explored graphene-VP40 interactions using molecular dynamics simulations and graphene pelleting assays. We found that graphene sheets associate strongly with VP40 at various interfaces. We also found that the graphene is able to disrupt the C-terminal domain (CTD-CTD) interface of VP40 hexamers. This VP40 hexamer-hexamer interface is crucial in forming the Ebola viral matrix and disruption of this interface may provide a method to use graphene or similar nanoparticle based solutions as a disinfectant that can significantly reduce the spread of the disease and prevent an Ebola epidemic

Adapting Livestock Production Systems to Climate Change in Nepal: Challenges and Opportunities

To assess climate change impacts and identify challenges and opportunities for livestock climate change adaption, we conducted a comprehensive study in the Thulokhola watershed of Nuwakot district in Nepal from June 1, 2011 to January 31, 2013. We established nine community livestock groups (CLGs) consisting of 51 members and trained the CLG members in daily livestock record keeping and monitoring surface water quality. Monthly fecal samples from 50 cattle, 50 goats, and 50 buffaloes were collected for the determination of gastrointestinal parasites. Soil and fodder samples were also collected and analyzed. Group discussions, Participatory Rural Appraisals, and full-fledged household survey of 97 households were done. A survey of 41 water sources in the watershed was also conducted. While 85.3 % of the water sources have either dried up or decreased in flow in recent years, drought conditions had great toll on agricultural production. Prevalence rates of helminthes on goats, cattle, and buffalo was 53.8%, 31.32%, and 23.52%, respectively, and animal deaths were remarkably high. Declining pregnancy rates on livestock along with waning supply of fodder and forages and poor soil quality were additional major problems. Although local communities have undertaken several measures including adding new breed, destocking, purchasing fodder and forages, and planting grasses for livestock climate change adaptation, the problems of animal health, breeding conditions, soil fertility, forest degradation, increasing women workload, and water shortages were largely unaddressed. Opportunities for livestock climate change adaptation in Nepal include agroforestry intervention, groundwater utilization, rainwater harvesting, enhancing feed efficiency, and community capacity-building

Cysteine mutations in the ebolavirus matrix protein VP40 promote phosphatidylserine binding by increasing the flexibility of a lipid-binding loop

Ebolavirus (EBOV) is a negative-sense RNA virus that causes severe hemorrhagic fever in humans. The matrix protein VP40 facilitates viral budding by binding to lipids in the host cell plasma membrane and driving the formation of filamentous, pleomorphic virus particles. The C-terminal domain of VP40 contains two highly-conserved cysteine residues at positions 311 and 314, but their role in the viral life cycle is unknown. We therefore investigated the properties of VP40 mutants in which the conserved cysteine residues were replaced with alanine. The C311A mutation significantly increased the affinity of VP40 for membranes containing phosphatidylserine (PS), resulting in the assembly of longer virus-like particles (VLPs) compared to wild-type VP40. The C314A mutation also increased the affinity of VP40 for membranes containing PS, albeit to a lesser degree than C311A. The double mutant behaved in a similar manner to the individual mutants. Computer modeling revealed that both cysteine residues restrain a loop segment containing lysine residues that interact with the plasma membrane, but Cys311 has the dominant role. Accordingly, the C311A mutation increases the flexibility of this membrane-binding loop, changes the profile of hydrogen bonding within VP40 and therefore binds to PS with greater affinity. This is the first evidence that mutations in VP40 can increase its affinity for biological membranes and modify the length of Ebola VLPs. The Cys311 and Cys314 residues therefore play an important role in dynamic interactions at the plasma membrane by modulating the ability of VP40 to bind PS