Nadya Farah, S.S., M.Si., Ph.D.

Preliminary investigation of radar-absorbing properties of sustainable fungal biocomposites

This study explores mycelium-based biocomposites as lightweight, radar-absorbing materials for drone structures. Four variants were developed: default composite (DC), rice husk composite (RHC), silica-enhanced composite (SC), and abaca-based composite (AC), with densities ranging from 0.14 to 0.29 g/cm3. Each exhibited distinct physical and visual characteristics and was evaluated using SEM, mechanical testing, and radar cross-section (RCS) reduction. Mechanical results showed that SC achieved the highest performance, with compressive strength of 160 ± 0.1 kPa and flexural strength of 8.39 ± 2.735 MPa. DC displayed balanced properties (117 ± 14.177 kPa; 7.12 ± 0.004 MPa), while AC offered moderate strength with lower density (100 ± 20.00 kPa; 6.10 ± 0.300 MPa). RHC demonstrated the weakest performance, highlighting the influence of reinforcement type. Radar absorption, measured across 4.3–8.5 GHz, revealed that SC achieved the highest absorption of 16.88 dB at 4.97 GHz. In contrast, conventional materials such as Mylea™, Bakelite, rubber, PE, and carbon fiber showed relatively low absorption. Overall, the results establish baseline performance. However, variations in thickness, microstructure, and homogeneity affect outcomes, indicating the need for further optimization. Future work should refine composite architecture, including fiber orientation, additive loading, and density control, to enhance broadband radar absorption.

BACTERICIDAL ACTIVITIES OF SELECTED MEDICINAL PLANTS AGAINST MULTI-DRUG RESISTANT UROPATHOGENIC ESCHERICHIA COLI STRAINS

Pathogenic microbes, including Bacillus thuringiensis, Staphylococcus, and Escherichia coli, commonly infect the urogenital tract, often leading to urinary tract infections (UTIs) in human.Due to bacterial resistance to antibiotics and their side effects have prompted researchers to seek natural alternatives.Medicinal herbs are the promising alternatives to antibiotics and synthetic drugs.Medicinal herbs, including Allium sativum (garlic), Zingiber officinale (ginger), and Nigella sativa (kalonji), are increasingly recognized in scientific research for their potent antimicrobial properties and therapeutic potential.This study evaluated the antibacterial potential of garlic, ginger, and kalonji extracts against UTI-causing pathogens.Fresh samples of these herbs were obtained from local markets in Lahore, and their extracts were prepared using ethanol, nhexane, and aqueous methods.Antimicrobial activity was assessed using the disc diffusion method, measuring inhibition of zones for bacterial biofilm formation, adherence, and motility.Results indicated that ethanol extracts of garlic and ginger exhibited the highest antibacterial activity, with inhibition zones of 10-11 mm against all tested pathogens.n-Hexane extracts showed moderate activity, while aqueous extracts were largely ineffective.Kalonji extracts demonstrated lower antimicrobial efficacy compared to garlic and ginger.The findings suggest that ethanol and n-hexane extracts of garlic and ginger are promising natural alternatives for treating UTIs caused by drug-resistant bacteria.

The Potential of Silica-Carbon Nanotubes Composite for Electromagnetic Absorber Coating

The utilization of shielding materials to absorb electromagnetic waves has been widely implemented, especially in military technology and equipment. In this study, we developed a composite material based on silicon dioxide ($\mathbf{S i O}_{2}$) and multi-walled carbon nanotubes (MWCNTs) to enhance the electromagnetic wave absorption compared to single material $\mathbf{S i O}_{2}$. In addition, a marine coating matrix was used in this research. The material characterization was done using scanning electron microscope (SEM) analysis to observe the surface morphology. Meanwhile, a vector network analyzer was used to determine scattering parameters at a frequency range of $4-8 \mathrm{GHz}$ and $8-12 \mathrm{GHz}$. The measurement results showed that the absorber layer of $\mathbf{S i O}_{2} /$ MWCNTs $\mathbf{2 w t} \%$ composite had the highest absorption coefficient of 34.37% at a frequency of 7.66 GHz.

Potential of invasive alien species Clidemia hirta as antibacterial against Salmonella typhi and Staphylococcus aureus

Abstract. Pratami MP, Fendiyanto MH, Satrio RD, Widana IDKK, Nikmah IA, Sari NIP, Awwanah M, Farah N, Darmadi D. 2021. Potential of invasive alien species Clidemia hirta as antibacterial against Salmonella typhi and Staphylococcus aureus. Biodiversitas 22: 3363-3369. Clidemia hirta D. Don is an invasive alien species (IAS) that is a threat to biodiversity in tropical country particularly Indonesia, and remains underutilized to date. Conversely, prevalence of typhus in Indonesia is generally higher every year. Thus, the aim of this study was to detect phytochemicals in ethanolic and aqueous extracts of C. hirta and their antibacterial activity against Salmonella typhi and Staphylococcus aureus. The research methods included sample identification, generating the simplicia, determination of water content, extraction, phytochemical screening tests, and antibacterial activity tests. Identification was made based on morphological characteristics. The water content in the dried powder of simplicia was 12.26 ± 0.39%. Phytochemical results showed that 70% ethanol extract of C. hirta contained flavonoids, saponins, tannins, and triterpenoids compounds. In addition, aqueous extract of C. hirta showed positive results on flavonoids, saponins, tannins, and steroids tests. Antibacterial activity results showed that ethanolic extracts of C. hirta inhibited S. typhi and S. aureus at all concentrations, while aqueous extract inhibited bacterial growth in only 12.5% ??and 25% concentrations. These findings indicate that C. hirta has antibacterial activity that inhibits S. typhi and S. aureus. This information can be used for adding preliminary data to metabolite interest researchers, i.e., biologists and biotechnologists in the future.

Synthetic Scaffold Systems for Increasing the Efficiency of Metabolic Pathways in Microorganisms

Microbes have been the preferred hosts for producing high-value chemicals from cheap raw materials. However, metabolic flux imbalance, the presence of competing pathways, and toxic intermediates often lead to low production efficiency. The spatial organization of the substrates, intermediates, and enzymes is critical to ensuring efficient metabolic activity by microorganisms. One of the most common approaches for bringing the key components of biosynthetic pathways together is through molecular scaffolds, which involves the clustering of pathway enzymes on engineered molecules via different interacting mechanisms. In particular, synthetic scaffold systems have been applied to improve the efficiency of various heterologous and synthetic pathways in Escherichia coli and Saccharomyces cerevisiae, with varying degrees of success. Herein, we review the recent developments and applications of protein-based and nucleic acid-based scaffold systems and discuss current challenges and future directions in the use of such approaches.

THE EFFECT OF SYNTHETIC FUNGICIDE ON DISEASE SEVERITY AND PLANT GROWTH OF CHILI PEPPER (Capsicum annuum L.) INFECTED WITH Phytophthora capsici

Phytophthora blight caused by Phytophthora capsici is one of the damaging diseases that cause major loss in chili pepper (Capsicum annuum L.) production worldwide. Some synthetic fungicides containing Metalaxyl-M were reported to be able to control the pathogen’s growth. In order to evaluate the effect of synthetic fungicide on disease severity index (DSI) and plant growth of chili pepper plants after inoculation with P. capsici (104 zoospores/ml), four cultivars were used namely Laba, Pilar, Arimbi and Imola. Each cultivar was treated with a synthetic fungicide and P. capsici (FP), with P. capsici-only (P) and uninoculated plants (C) were used as controls. The result showed that the application of synthetic fungicide was able to control the pathogen’s growth, indicated by the decreased DSI. The application of synthetic fungicide was also able to preserve the growth of chili pepper plants, indicated by the plant height and number of leaves, even after the infection with P. capsici. In conclusion, the application of synthetic fungicide was effective in controlling the growth of P. capsici while preserving the growth of chili pepper plants in cultivar Pilar, Imola, Laba, and Arimbi.

SIX6 Shows High Divergence in Fusarium oxysporum f. sp. cubense TR4

Secreted fungal effector proteins and their host targets are good examples to understand the mechanism of host-pathogen co-evolution with genes involved in the interaction undergoing positive selection. SIX genes (secreted in xylem) are obtained via horizontal transfer and can be found within the formae speciales of Fusarium oxysporum. SIX6 and SIX9 of F. oxysporum f. spp. cubense (Foc) are predicted to play a role as effectors. However, their involvement in the pathogenicity of Foc in banana plants has not been determined yet. In the susceptible banana cultivar, we found that the SIX6 and SIX9 genes of Foc TR4 were highly expressed in roots, but not in corms or leaves. The host, however, expressed the pathogenesis-related (PR) genes, PR-1 and PR-3, in corms earlier than in the roots. Phylogenetic analysis on SIX6 and SIX9 genes of F. oxysporum has revealed the separation of SIX6 and SIX9 of Foc from other formae speciales. This leads to detecting genes under positive selection using the ratio nonsynonymous to synonymous substitution rates (Ka/Ks). SIX6 of Foc showed an increase in diversity, but insufficient to drive positive selection. Conversely, SIX9 of Foc showed no divergence in the dN/dS ratio distribution, indicating purifying selection. © 2021 Friends Science Publishers

Comparative Study of Nano-chitosan and Synthetic Bactericide Application on Chili Pepper (Capsicum annuum L.) Infected by Xanthomonas campestris

Nano-chitosan is considered as a prospective replacement for synthetic bactericides. In this study, the antibacterial activity of nano-chitosan and synthetic bactericides was compared in four chili pepper cultivars (Bianca, Lado, Kiyo, and Tanamo) infected by Xanthomonas campestris. To assess the effect of nano-chitosan and synthetic bactericide on the growth of the X. campestris-infected chili pepper plants, some parameters were observed including the plant height, number of leaves and chlorophyll content. It was shown that nano-chitosan was highly effective in controlling the pathogen infection on Bianca, Lado, and Tanamo, but not significant on Kiyo. The application of synthetic bactericide, however, was effective on Bianca and Lado, but not significant on Kiyo and Tanamo. It was also shown that the application of nano-chitosan can improve the growth of the X. campestris-infected chili pepper plants based on the significant difference on the plant height, number of leaves and chlorophyll content of cultivars tested, especially in Kiyo, Lado, and Tanamo. The application of synthetic bactericide, however, did not significantly improve the growth of the X. campestris-infected chili pepper plants. Nano-chitosan was shown to be effective in reducing the infection of X. campestris and potentially be used as an alternative to synthetic bactericide.

Data on banana transcriptome in response to blood disease infection

Blood disease of Banana (BDB) is one of the prevalent disease caused by Ralstonia syzygii subsp. celebesensis (Rsc) which cause substantial loss on banana production in Indonesia. To date, the genetic basis of plant defense mechanism caused by blood disease in banana is not available. As a matter of fact, the knowledge of global gene expression will provide important information on plant response to the pathogen infection. Data from transcriptomic analysis in response to blood disease infection from Musa acuminata cv. Mas Kirana (AA group), representing the A genome, and Musa balbisiana cv. Klutuk (BB group), representing the B genome, were firstly reported. The transcriptome data discussed in this publication are accessible through NCBI's Gene Expression Omnibus with GEO Series accession number GSE138749. These data provide the basis for further investigation on the global gene expression which is pivotal to understand the mechanism of disease resistance from two banana genomes in response to blood disease infection.

Functional Characterisation of the Flax Rust AvrP/AvrP123 Avirulence Proteins

Flax rust effector proteins AvrP and AvrP123 are recognised by the flax resistance proteins, P and P1, P2, P3, respectively. Variants of these effectors with different host-recognition specificities are found in the flax rust strains 271, 339, bs25 and WA. In this study, investigation was conducted on regions in AvrP and AvrP123 that are recognised by their cognate resistance proteins. Agrobacterium-mediated expression of AvrP and AvrP123 variants in tobacco (Nicotiana tabacum) and flax (Linum usitatissimum) was used to observe necrosis induction as an indicator of recognition. For AvrP, deletions were generated based on the structure of the protein, whereas domain swaps and mutations were generated based on amino acid polymorphisms present in the AvrP variant from strain 271, which is not recognised by P, P1, P2 or P3. Amino acid polymorphisms involved in AvrP recognition were found to be located near the C-terminus of the protein. From the structure of AvrP, it was known that AvrP and AvrP123 each bind three zinc atoms. Mutational disruption of zinc binding in AvrP resulted in a loss of protein stability and a loss of recognition by P. For AvrP123, deletions and domain swaps were generated based on amino acid polymorphisms present in AvrP123 variants from strains 339, bs25 and WA. Recognition or AvrP123 by P1 was found to be determined by the mature N-terminal region of the protein just after the signal peptide, whereas P2 and P3 were found to recognise the C-terminal region of AvrP123. In an attempt to find interactor proteins targeted by AvrP in host cells, a yeast-two hybrid assay was conducted using cDNA library derived from rust-infected flax leaves. Four candidates were identified, one candidate from the pathogen, designated SIAP (Secreted Interactor of AvrP) and three candidates from the host, phosphoglucomutase, peptidyl-prolyl cis-trans isomerase FKBP12, and DEAD-box ATP-dependent RNA helicase 56. Each of these candidates is a plausible target for AvrP effector function in the plant cells, but further analysis is required to confirm these interactions and to determine the effect of AvrP on interactor function.

Crystal structure of the Melampsora lini effector AvrP reveals insights into a possible nuclear function and recognition by the flax disease resistance protein P

The effector protein AvrP is secreted by the flax rust fungal pathogen (Melampsora lini) and recognized specifically by the flax (Linum usitatissimum) P disease resistance protein, leading to effector-triggered immunity. To investigate the biological function of this effector and the mechanisms of specific recognition by the P resistance protein, we determined the crystal structure of AvrP. The structure reveals an elongated zinc-finger-like structure with a novel interleaved zinc-binding topology. The residues responsible for zinc binding are conserved in AvrP effector variants and mutations of these motifs result in a loss of P-mediated recognition. The first zinc-coordinating region of the structure displays a positively charged surface and shows some limited similarities to nucleic acid-binding and chromatin-associated proteins. We show that the majority of the AvrP protein accumulates in the plant nucleus when transiently expressed in Nicotiana benthamiana cells, suggesting a nuclear pathogenic function. Polymorphic residues in AvrP and its allelic variants map to the protein surface and could be associated with differences in recognition specificity. Several point mutations of residues on the non-conserved surface patch result in a loss of recognition by P, suggesting that these residues are required for recognition.

Low cost HIV-1 quantitative RT-PCR assay in resource-limited settings: Improvement and implementation