Silver nanoparticles are one of the most extensively studied nanomaterials due to their high stability and low chemical reactivity in comparison to other metals. They are commonly synthesized using toxic chemical reducing agents which reduce metal ions into uncharged nanoparticles. However, in the last few decades, several efforts were made to develop green synthesis methods to avoid the use of hazardous materials. The natural biomolecules found in plants such as proteins/enzymes, amino acids, polysaccharides, alkaloids, alcoholic compounds, and vitamins are responsible for the formation of silver nanoparticles. The green synthesis of silver nanoparticles is an eco-friendly approach, which should be further explored for the potential of different plants to synthesize nanoparticles. In the present review we describe the green synthesis of nanoparticles using plants, bacteria, and fungi and the role of plant metabolites in the synthesis process. Moreover, the present review also describes some applications of silver nanoparticles in different aspects such as antimicrobial, biomedicine, mosquito control, environment and wastewater treatment, agricultural, food safety, and food packaging.

Amphotericin B is increasingly used in treatment of leishmaniasis. Here, fourteen independent lines of Leishmania mexicana and one L. infantum line were selected for resistance to either amphotericin B or the related polyene antimicrobial, nystatin. Sterol profiling revealed that, in each resistant line, the predominant wild-type sterol, ergosta-5,7,24-trienol, was replaced by other sterol intermediates. Broadly, two different profiles emerged among the resistant lines. Whole genome sequencing then showed that these distinct profiles were due either to mutations in the sterol methyl transferase (C24SMT) gene locus or the sterol C5 desaturase (C5DS) gene. In three lines an additional deletion of the miltefosine transporter gene was found. Differences in sensitivity to amphotericin B were apparent, depending on whether cells were grown in HOMEM, supplemented with foetal bovine serum, or a serum free defined medium (DM). Metabolomic analysis after exposure to AmB showed that a large increase in glucose flux via the pentose phosphate pathway preceded cell death in cells sustained in HOMEM but not DM, indicating the oxidative stress was more significantly induced under HOMEM conditions. Several of the lines were tested for their ability to infect macrophages and replicate as amastigote forms, alongside their ability to establish infections in mice. While several AmB resistant lines showed reduced virulence, at least two lines displayed heightened virulence in mice whilst retaining its resistance phenotype, emphasising the risks of resistance emerging to this critical drug.

Leptospirosis has been reported as an endemic in most tropical countries. Among high risk occupations, leptospirosis includes workers in agriculture and domestic animal industries. Environmental hygiene in the wet market has established a link between the presence of rodents with probability of leptospirosis infection. This study was aimed to compare the level of knowledge, attitude and preventive practice against leptospirosis between healthy Malaysian and non-Malaysian wet market workers in selected wet markets in urban areas of Selangor. A cross-sectional study in the determined area was conducted with the participation of 147 respondents. The respondents were randomly chosen from the list provided by the state agency that regulates these markets. A self-administered bilingual validated questionnaire (English and Bahasa Melayu) was distributed to the selected respondents. There were 68 (48.3%) Malaysian respondents and 79 (53.7%) non-Malaysian respondents. The majority of them were males, who attained formal education and were less than 40 years old. Meanwhile, the respondents earned less than RM3000. Among the Malaysian respondents, 80.9% were aware of leptospirosis as compared to 17.7% of the non-Malaysian colleagues (p < 0.05). All items of knowledge showed that the Malaysian respondents scored higher as compared to non-Malaysian respondents. On attitude towards infection prevention, most Malaysian respondents had a positive attitude, while most non-Malaysian respondents had undecided perception on the majority of crucial attitude items. In practicing preventive measures, there was a marked significant difference in proportion between Malaysian and non-Malaysian respondents for items on “Specific Protection and Isolation at Source.” There was a significant gap on knowledge, attitude and preventive practice among Malaysian workers as compared to non-Malaysian workers. Therefore, it was highly recommended the health promotion implementation should also provide specific focus on non-Malaysian workers.

The main factors in reducing foodborne outbreaks are good knowledge, attitude, practice, and perception (KAP2) of food poisoning prevention. Nevertheless, limited KAP2 studies have been conducted among consumers, particularly in rural areas. Thus, this preliminary study was conducted to evaluate the current level of food poisoning prevention KAP2 before intervention among 100 voluntary consumers in Kuala Nerus, Terengganu, selected through a non-probability convenience sampling. The KAP2 questionnaire was used and consists of five sections: socio-demographic, knowledge (42 items), attitude (10 items), practices (10 items), and perception (5 items). The scoring method used the original Bloom’s cut-off points with good level: 80%-100%; moderate level: 60-79%; and poor level: <59%. Overall, the results showed a moderate knowledge’s level with a median knowledge score of 29.0 (IQR 7.0) out of 42.0, a positive attitude with 46.0 (IQR 7.0) out of 50.0, good practice’s level with 34.0 (IQR 5.0) out of 40.0, and a moderate perception’s level on food poisoning prevention with 17.5 (IQR 4.0) out of 25.0. In conclusion, evaluating KAP2 before intervention is essential in developing an efficient educational program.

Amphotericin B is increasingly used in treatment of leishmaniasis. Here, fourteen independent lines of Leishmania mexicana and one L. infantum line were selected for resistance to either amphotericin B or the related polyene antimicrobial, nystatin. Sterol profiling revealed that, in each line, the predominant ergostane-type sterol of wild-type cells was replaced by other sterol species. Broadly, two different profiles emerged among the resistant lines. Whole genome sequencing then showed that these distinct profiles were due either to mutations in the sterol methyl transferase (C24SMT) gene locus or the sterol C5 desaturase (C5DS) gene. In three lines an additional deletion of the miltefosine transporter was found. Differences in sensitivity to amphotericin B were apparent, depending on whether cells were grown in HOMEM, supplemented with foetal bovine serum, or a serum free defined medium (DM). These differences appeared to relate to the presence of lipids in the former. Metabolomic analysis after exposure to AmB showed that a large increase in glucose flux via the pentose phosphate pathway preceded cell death in cells sustained in HOMEM but not DM, indicating the oxidative stress was more significantly induced under HOMEM conditions. Several of the lines were tested for ability to infect macrophages and replicate as amastigote forms, alongside their ability to establish infections in mice. While several lines showed reduced virulence, at least one AmB resistant line displayed heightened virulence in mice whilst retaining its resistance phenotype, emphasising the risks of resistance emerging to this critical drug.