BackgroundBreast cancer is the most common cancer and a major cause of death in women, makes up about one-tenth of all new cancer diagnoses worldwide. Breast cancer and other cancer forms are heterogeneous diseases with varied morphological appearances, molecular features, behavior, and response to therapies (using surgery, chemotherapy, radiation therapy and targeted therapy). Despite the achievement of objective responses, the available treatments are associated with significant limitations in safety and efficacy. Several plant products (barks, leaves, flowers, roots, fruits, seeds) have been characterized as effective in cancer chemoprevention with minimal or no side effects.AimsThis study is aimed at evaluating the antiproliferative potential of aqueous leaf extract of Mucuna pruriens on 7,12-dimethylbenzeneanthracene (DMBA)-induced-breast cancer in female albino rats.Materials and methodsM. pruriens, thirty (30) female albino rats and 7,12-dimethylbenzeneanthracene were used for this study. Hot extraction protocol was employed in the preparation of aqueous extract of M. pruriens leaves. Qualitative and quantitative phytochemical screening of aqueous leaf extract of M. pruriens and weight determination was employed using standard protocol. Comet assay protocol was employed to determine level of deoxyribonucleic acid (DNA) fragmentation while hematoxylin and eosin were used for histological assay.ResultsPhytochemical screening revealed the presence of alkaloids, reducing sugar, anthraquinones, flavonoids, saponins, tannins, cardiac glycosides, phenols and steroids. Flavonoid was quantitatively determined to be present in the highest amount. Histological assay revealed the presence of atrophy of seromucous glands with surrounding stromal fibrosis and hyperplasia of serous and mucinous. There was a significant weight difference between the control and treatment groups. Determination of length and weight of isolated tumor from rat induced with DMBA only was 2.4cm and 2.8g respectively. DNA smears obtained from single cell gel electrophoresis (SCGE) suggested possible DMBA-induced damage which was significantly prevented owing to the effect of the leaf extract of M. pruriens.ConclusionThis study has shown that the leaf extract of M. pruriens could be used as a prophylactic measure against DMBA-induced cell proliferation in the breast tissues of female albino rats

Nanosilver was synthesised by bioreduction using aqueous extracts of

Split inteins are biological mechanisms for the operation of the spatiotemporal control of protein activities. They function through protein trans-splicing, in which their N- and C-terminal fragments are expressed contiguously with two protein halves. The subsequent self-excision upon recognition of the complimentary fragment yields a mature, complete, and functional protein. The conditional regulation of protein splicing through environmental factors or the attachment of regulatory modules can be used to determine when and where a protein will operate, providing potential novel approaches for engineering biology applications. This review will discuss current split intein applications and the mechanistic basis for novel species classification. These considerations can provide guidance in intein and extein engineering through activation strategies, in the design of spatial arrangements, and in taking advantage of unique reaction environments. This can pave the way for the future implementation of novel split intein discoveries and the selection of appropriate intein species and aid in designing novel protein engineering strategies.

Advances in synthetic biology have led to the design of biological parts that can be assembled in different ways to perform specific functions. For example, genetic circuits can be designed to execute specific therapeutic functions, including gene therapy or targeted detection and the destruction of invading viruses. Viral infections are difficult to manage through drug treatment. Due to their high mutation rates and their ability to hijack the host’s ribosomes to make viral proteins, very few therapeutic options are available. One approach to addressing this problem is to disrupt the process of converting viral RNA into proteins, thereby disrupting the mechanism for assembling new viral particles that could infect other cells. This can be done by ensuring precise control over the abundance of viral RNA (vRNA) inside host cells by designing biological circuits to target vRNA for degradation. RNA-binding proteins (RBPs) have become important biological devices in regulating RNA processing. Incorporating naturally upregulated RBPs into a gene circuit could be advantageous because such a circuit could mimic the natural pathway for RNA degradation. This review highlights the process of viral RNA degradation and different approaches to designing genetic circuits. We also provide a customizable template for designing genetic circuits that utilize RBPs as transcription activators for viral RNA degradation, with the overall goal of taking advantage of the natural functions of RBPs in host cells to activate targeted viral RNA degradation.

Integrases from the “large serine” family are simple, highly directional site-specific DNA recombinases that have great promise as synthetic biology and genome editing tools. Integrative recombination (mimicking phage or mobile element insertion) requires only integrase and two short (∼40 – 50) DNA sites. The reverse reaction, excisive recombination, does not occur until it is triggered by the presence of a second protein termed a Recombination Directionality Factor (RDF), which binds specifically to its cognate integrase. Identification of RDFs has been hampered due to their lack of sequence conservation and lack of synteny with the phage integrase gene. Here we use Alphafold2-multimer to identify putative RDFs for more than half of a test set of 98 large serine recombinases, and experimental methods to verify predicted RDFs for 4 of 5 integrases chosen as test cases. We find no universally conserved structural motifs among known and predicted RDFs, yet they are all predicted to bind a similar location on their cognate integrase, suggesting convergent evolution of function. Our methodology greatly expands the available genetic toolkit of cognate integrase – RDF pairs.

To search for a novel thermostable esterase for optimized industrial applications, esterase from a thermophilic eubacterium species, Thermoanaerobacter tengcongensis MB4, was purified and characterized in this work. Sequence analysis of T. tengcongensis esterase with other homologous esterases of the same family revealed an apparent tail at the C-terminal that is not conserved across the esterase family. Hence, it was hypothesized that the tail is unlikely to have an essential structural or catalytic role. However, there is no documented report of any role for this tail region. We probed the role of the C-terminal domain on the catalytic activity and substrate preference of T. tengcongensis esterase EstA3 with a view to see how it could be engineered for enhanced properties. To achieve this, we cloned, expressed, and purified the wild-type and the truncated versions of the enzyme. In addition, a naturally occurring member of the family (from Brevibacillus brevis) that lacks the C-terminal tail was also made. In vitro characterization of the purified enzymes showed that the C-terminal domain contributes significantly to the catalytic activity and distinct substrate preference of T. tengcongensis esterase EstA3. All three recombinant enzymes showed the highest preference for paranitrophenyl butyrate (pNPC4), which suggests they are true esterases, not lipases. Kinetic data revealed that truncation had a slight effect on the substrate-binding affinity. Thus, the drop in preference towards long-chain substrates might not be a result of substrate binding affinity alone. The findings from this work could form the basis for future protein engineering allowing the modification of esterase catalytic properties through domain swapping or by attaching a modular protein domain.