Saudi Journal of Biological Sciences最新文献

Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), is an economically important invasive cassava pest responsible for the massive devastation of cassava in Asia and African continent. Initially, identifying this invasive pest posed challenges because it closely resembled native mealybug species. Additionally, the traditional morphological identification process is labor-intensive and time-consuming. Detecting invasive pests at an early stage is crucial, hence development of a rapid detection assay is essential. In the current study, we have developed a simple, rapid, sensitive, and efficient molecular detection assay for P. manihoti based on Recombinase Polymerase Amplification (RPA). The primers for the RPA assay were designed using unique nucleic acid sequences of P. manihoti, and the protocol was standardized. Specificity test demonstrated that the RPA assay could amplify DNA of P. manihoti only, and no amplification was observed in six other mealybug species. The specificity of assay was confirmed using SYBR green-based colorimetric detection and gel electrophoresis where positive samples showed 195 bp amplicon size in P. manihoti samples. The assay successfully amplified P. manihoti DNA in thirty minutes at an annealing temperature of 41° C in a water bath and displayed a sensitivity of 72.5 picograms per microliter. The assay's simplicity, rapidity, and high sensitivity make it a valuable tool for detecting and monitoring P. manihoti in quarantine stations and facilitating in development of a portable diagnostic kit.

The genus Landolphia (P. Beauv.) belongs to the Apocynaceae family with over 65 species distributed all over the tropical regions. This genus has a considerable number of documented medicinal, industrial, and ecologically beneficial effects. Therefore, this review is tailored towards the appraisal of the traditional significance, phytochemistry, and pharmacological activities of the genus Landolphia. This will help researchers understand future research trends by bridging the gaps between documented literature and contemporary uses. Relevant information was obtained from selection of scientific databases such as Web of Science, PubMed, Scopus, Google Scholar, ScienceDirect and Wiley. From documented literature, different parts of Landolphia have been used to improve fertility, lessen menstrual pain, boost sex libido, cure malaria and typhoid. Several classes of bioactive constituents such as terpenoids, phenolics, flavonoids, steroids, fatty acids, saponins, phytosterol and phenylpropanoid, volatile compounds, lignans and coumarins have been isolated from this genus. These secondary metabolites could be responsible for the reported antimicrobial, antimalarial, aphrodisiac, antioxidant, anti-inflammatory, antidiabetic and anticancer activities exhibited by this genus. The leaves, flower, bark and root of this genus have a wide range of essential nutrients and antinutrients which are essential for normal growth and development in living organisms. Despite all findings indicating the economical, industrial and pharmacological activities of Landolphia species, secondary metabolites and pharmacological potency of Landolphia of this genus are not adequately documented. Therefore, bioassay-guided isolation on the Landolphia extracts with proven biological activities should be prioritised in order to isolate pharmacophores with unique structural frameworks.

Bacterial contamination and infection widely affect the food, pharmaceutical and biomedical industries. Additionally, these bacteria developed resistance to synthetic antibiotics causing public health danger, globally. Natural plant extracts (NPE) are suitable alternatives to synthetic antibiotics to tackle antimicrobial resistance problems. Furthermore, a blend or combination of different NPEs exerts a wide spectrum of antimicrobial activity. Therefore, the combined effect of brazilin-rich extract (BRE) and lawsome methyl ether (LME) against infection-causing common bacteria were evaluated. BRE had a lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against most of the Gram-negative bacteria (Salmonella typhi, Salmonella typhimurium and Pseudomonas aeruginosa) while LME was active against most of the Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis). The combination of BRE and LME at 2:1 and 1:1 concentration significantly reduced the MIC value of each compound as compared to either BRE or LME concentration alone (P < 0.05). Further time-kill kinetics revealed a 3.0–3.5 log reduction in Gram-positive bacteria and a 2.5–3.0 log reduction in Gram-negative bacteria during 120 min of incubation, respectively. Therefore, a combination of BRE and LME was recommended as natural antibacterial to synthetic antibiotics for food and pharmaceutical applications.

Pseudomonas aeruginosa is a Gram-negative opportunistic bacterium, ubiquitously found in nature and causative agent in many infections. Due to increased antibiotic resistance, there is a need to develop more robust antibacterial agents from natural sources. In this study, we worked on two metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa strains and targeted the Quorum Sensing mechanism (QS) of these bacteria to combat antibiotic resistance. Our study aimed at using phytochemicals which have been used since centuries in herbal medicine. We used fifteen commercially available phytochemicals and check their effects on biofilm formation, quorum sensing and inter-related mechanisms. Sub-inhibitory concentration of isoliquiritin inhibited biofilm formation 55 % in P8 at day 6 and 48 % in P6 at day 6; quorum sensing 83 % in P6 and 61 % in P8 whereas sub-inhibitory concentration of 6-gingerol suppressed biofilm formation by 48 % in P8 at day 6 and 44 % in P6 at day 6; quorum sensing 69 % in P6 and 48 % in P8, respectively. The results indicated isoliquiritin, epigallocatechin gallate, eugenol, luteolin and chrysin to be the potential candidates in inhibiting QS and related mechanisms. Isoliquiritin which was never been used before against biofilm and QS related studies, showed remarkable results and found to be more efficient in inhibiting QS than 6-gingerol –a known QS inhibitor. For examining the molecular interaction between phytochemicals and QS, In-silico molecular docking was performed between phytoligands and four QS proteins (Las I, Las R, RhlI and Rhl R). In-silico docking analysis revealed that isoliquiritin showed strong bond with amino acids (Trp34, Asp35, Asp35, Tyr105, Arg104, Val138, Thr140) present at the active site of RhlI with binding energy value of −8.4 kcal/mol as compared to that of 6-gingerol with Rhl1 (−7.3 kcal/mol). In conclusion, our study may help in controlling nosocomial infections caused by carbapenem-resistant metallo beta-lactamase P. aeruginosa (MBL-PA) by utilizing these phytochemicals in biofilms disruption and quorum sensing inhibition. Moreover their synergism with antibiotics may help in lowering the MIC of carbapenem antibiotics against such Multi-drug resistant strains.

The most effective methodologies for generating Musa spp. explants involve the utilization of plant tissue culture micropropagation techniques. However, the pervasive challenge of microbial contamination significantly impedes the successful micropropagation of Musa spp. This study examined the antioxidant and antibacterial characteristics of the essential oil (LPO) and extract (LPE) obtained from the peel of Citrus aurantifolia. Additionally, we explored their mechanisms against common microbial contaminants in Musa spp. micropropagation. Using gas chromatography-mass spectrometry, we identified 28 components in LPO, with δ-limonene, β-pinene, citral, trans-citral, β-bisabolene, geranyl acetate, and α-pinene as the primary constituents. Meanwhile, liquid chromatography-mass spectrometry detected 17 components in LPE, highlighting nobiletin, tangeretin, scoparone, sinensetin, tetramethylscutellarein, 5-demethylnobiletin, and pyropheophorbide A as the predominant compounds. Evaluation using the DPPH and ABTS methods revealed the IC₅₀ values for LPE at 0.66 ± 0.009 and 0.92 ± 0.012 mg/mL, respectively, indicating higher antioxidant activity compared to LPO, with IC₅₀ values of 3.03 ± 0.019 and 4.27 ± 0.023 mg/mL using the same methods. Both LPO and LPE exhibited antimicrobial activities against all tested contaminant microorganisms through in vitro assays. Mechanistic investigations employing time-kill analysis, assessment of cell membrane integrity, and scanning electron microscopy (SEM) revealed changes in the morphological characteristics of the tested microbial contaminants, intensifying with increased concentration and exposure duration of LPO and LPE. These alterations led to substantial damage, including cell wall lysis, leakage of intracellular components, and subsequent cell death. Consequently, LPO and LPE emerge as promising alternatives for addressing microbial contamination in banana tissue cultures.

The dairy industry is reshaping itself and becoming commercialized in Pakistan due to the increased demand for milk to overcome the shortage. Exotic breeds such as Holstein Friesian, a high milk producing breed have started being reared more on farms in Pakistan. Along with other issues, mastitis does affects the milk production of this breed. The objective of this study was to evaluate the milk composition in terms of bacterial communities in Holstein Friesian reared in Punjab, Pakistan and alteration in microbial composition with healthy and mastitic udder. Milk samples (n = 36) from farms rearing Holstein Friesian were collected. Among these samples, 05 samples from each three groups, HHF(healthy), CHF (clinical mastitis) and SHF (subclinical mastitis), based on their udder health condition, were processed using the 16 S r=RNA gene based technique. Diversity assessment as carried out by alpha diversity indices showed that milk samples from the udder infected with clinical mastitis were the least diverse and those from the healthy udder were more diverse. Beta diversity across samples showed a scattered pattern suggesting overlap amongst bacterial communities across different groups samples as depicted by PCA plots of beta diversity indices. The taxonomic profile revealed that Proteobacteria Firmicutes, Bacteroidota and Actinobacteriota were the major phyla detected across all groups. Proteobacteria dominated the HHF and SHF group while abundance of Firmicutes was higher in CHF group. Differences at other levels including order, genus and species were also recorded. The overall picture concludes that diverse microbiota is associated with different udder health conditions.

Botanical pesticides are safe and widely used in pest management. Curcuma angustifolia belongs to the family Zingiberaceae and is a rhizomatous medicinal herb. Following rhizome harvesting, leaves are discarded as waste. However, they can be effectively utilized by extracting essential oils, which are potential biopesticides. The aim of the study is to evaluate the efficacy of the leaf essential oil of Curcuma angustifolia as a potential biopesticide against three stored grain pests, Lasioderma serricorne, Tribolium castaneum, and Callasobruchus chinensis, by their contact, fumigant, and repellent activities. The leaves yield 0.39 ± 0.02 % of oil by hydrodistillation. GC–MS/MS characterization identified curzerenone (18.37 %), geranyl-p-cymene (17.32 %), α-elemenone (13.59 %), eucalyptol (7.58 %) as the main constituents. When exposed to different concentrations of C. angustifolia oil, the test insect displayed noticeably high repellency rates. It also showed better contact toxicity at 24 h, LC₅₀ = 0.22 mg/cm² for cigarette beetle, LC₅₀ = 0.64 mg/cm² for red flour beetle, LC₅₀ = 0.07 mg/cm² for pulse beetle) and fumigation toxicities (LC₅₀ = 10.8 mg/L air at 24 h, for cigarette, LC₅₀ = 29.5 mg/L air for red flour beetle, LC₅₀ = 7.9 mg/L air for pulse beetle). Additionally, a phytotoxicity study was done on paddy seeds, and the results showed no effect on seed germination or seedling growth. It was evident from this study that C. angustifolia oil from waste leaves can be utilized as a botanical pesticide to manage the adults of these storage pests.

This study investigated the impact of a mixture of six endophytic bacterial strains isolated from cucumber plants on the growth and microbiome diversity of six cucumber traditional varieties and hybrids. Six bacterial species were isolated and identified by 16 s rRNA sequencing. All the bacteria showed plant growth promoting traits. Bacillus tequilensis showed 80 % inhibition of the mycelia growth of Fusarium oxysporum f.sp. cucumarinum (Foc). Mixed culture of all the bacteria was prepared and applied back to the varieties and hybrids of cucumber plants through seed soaking. Plant growth characteristics indicated that the treated plants showed increased plant growth in terms of plant height, number of leaves, vine length, male:female flower ratio, number of fruits and fruit length. Bacteria treated plants of hybrid HiVeg Chitra recorded 19 cm increase in vine length compared to control plants. The matataxonomic analysis of leaf samples by Illumina sequencing highlighted a diverse bacterial community shift in treated plants, with significant increases in genera like Bacillus and Staphylococcus. The core microbiome analysis identified key genera such as Bacillus, Staphylococcus, Sphingomonas, Methylobacterium, etc that could be pivotal in plant growth promotion. Bacillus and Staphylococcus showed increased abundance in treated varieties, correlating with the observed in plant growth parameters thus indicating their role in growth promotion of cucumber plants. Endophytic bacterial species identified from cucumber plants when re-applied by seed soaking, they promote the plant growth by modulating the microbiome. The bacterial species identified in the study could be potential candidates as microbial bioinputs for cucumber cultivation.

Alzheimer's disease (AD) continues to be a worldwide health concern, demanding innovative therapeutic approaches. This study investigates the neuroprotective potential of herbal compounds by scrutinizing their interactions with Beta-Secretase-1 (BACE1). Through comprehensive molecular docking analyses, three compounds, Masticadienonic acid (ΔG: −9.6 kcal/mol), Hederagenin (ΔG: −9.3 kcal/mol), and Anthocyanins (ΔG: −8.1 kcal/mol), emerge as promising BACE1 ligands, displaying low binding energies and strong affinities. ADME parameter predictions, drug-likeness assessments, and toxicity analyses reveal favorable pharmacokinetic profiles for these compounds. Notably, Masticadienonic Acid exhibits optimal drug-likeness (−3.3736) and negligible toxicity concerns. Hederagenin (drug-likeness: −5.3272) and Anthocyanins (drug-likeness: −6.2041) also demonstrate promising safety profiles. Furthermore, pharmacophore modeling elucidates the compounds' unique interaction landscapes within BACE1′s active site. Masticadienonic acid showcases seven hydrophobic interactions and a hydrogen bond acceptor interaction with Thr232. Hederagenin exhibits a specific hydrogen bond acceptor interaction with Trp76, emphasizing its selective binding. Anthocyanins reveal a multifaceted engagement, combining hydrophobic contacts and hydrogen bond interactions with key residues. In conclusion, Masticadienonic acid, Hederagenin, and Anthocyanins stand out as promising candidates for further experimental validation, presenting a synergistic balance of efficacy and safety in combating AD through BACE1 inhibition.