Cutibacterium acnes is one of the most common bacterial species residing on the human skin. Although the pathogenic properties of C. acnes , such as its association with acne vulgaris, have been widely described, its beneficial aspects have not been well characterized.
The anthelmintic paraherquamide A acts selectively on the nematode L-type nicotinic acetylcholine receptors (nAChRs) but the mechanism of its selectivity is unknown. This study targeted the basis of paraherquamide A selectivity by determining an X-ray crystal structure of the acetylcholine binding protein (AChBP), a surrogate nAChR ligand-binding domain, complexed with the compound and by measuring its actions on wild-type and mutant Caenorhabditis elegans nematodes and functionally expressed C. elegans nAChRs. Paraherquamide A showed a higher efficacy for the levamisole-sensitive (L-type (UNC-38/UNC-29/UNC-63/LEV8/LEV-1)) nAChR than the nicotine-sensitive (N-type (ACR-16)) nAChR, a result consistent with in vivo studies on wild type worms and worms with mutations in subunits of these two classes of receptors. The X-ray crystal structure of the Ls-AChBP-paraherquamide A complex and site-directed amino acid mutation studies showed for the first time that loop C, loop E and loop F of the orthosteric receptor binding site play critical roles in the observed L-type nAChR selective actions of paraherquamide A. Significance Statement Paraherquamide A, an oxindole alkaloid, has been shown to act selectively on the L-type over N-type nAChRs in nematodes, but the mechanism of selectivity is unknown. We have co-crystallized paraherquamide A with the acetylcholine binding protein, a surrogate of nAChRs, and found that structural features of loop C, loop E and loop F contribute to the L-type nAChR selectivity of the alkaloid. The results create a new platform for the design of anthelmintic drugs targeting cholinergic neurotransmission in parasitic nematodes.
Lactococcus lactis subsp. lactis exhibits probiotic properties in humans. Considering that Caenorhabditis elegans can be used to study the effects of microorganisms on animal behavior, owing to its simple nervous system, we assessed the impacts of two strains of Lactococcus lactis subsp. Lactis—a non-nisin-producing strain, NBRC 100933 (LL100933), and a nisin-producing strain, NBRC 12007 (LL12007)—on the lifespan, locomotion, reproductive capacity of, and lipid accumulation in, C. elegans. The lifespan of adult C. elegans fed a mixture (1:1) of Escherichia coli OP50 and LL100933 or LL12007 did not show a significant increase compared to that of the group fed a standard diet of E. coli OP50. However, the nematodes fed Lactococcus strains showed notable enhancement in their locomotion at all of the tested ages. Further, the beneficial effects of LL100933 and LL12007 were observed in the daf-16 mutants, but not in the skn-1 and pmk-1 mutants. The lipid accumulation in the worms of the Lactococcus-fed group was lower than that in the control group at all experimental ages. Overall, LL100933 and LL12007 enhance the locomotor behavior of C. elegans, likely by modulating the PMK-1/p38 MAPK and SKN-1/Nrf2 transcription factors.
23 February 2019 in Journal of Food Quality and Hazards Conrol
Background: Milk is considered as one of the highly nutritious food for human. This study was undertaken to evaluate the physicochemical as well as the microbial quality of pasteurized milk of different brands available in Chittagong, Bangladesh. Methods: Five types of branded pasteurized liquid milk were collected from retail markets of Chittagong, Bangladesh. Physicochemical analyses were carried out in order to determine the levels of pH, acidity, fat, protein, casein, specific gravity, Solids-Not-Fat (SNF), and total solids of the samples. Also, the samples were analyzed microbiologically to assess the total microbial loads and coliforms. Statistical analysis was done using SPSS software version 23.0. Results: The ranges of physicochemical parameters of the samples were determined, including specific gravity (1.024-1.031), pH (5.8-6.7), acidity (0.17±0.01-0.37±0.01%), total solids content (8.17-12.27%), SNF (7.28-8.49%), fat (0.89-3.78%), protein (3.42±0.09-3.63±0.02%), and casein content (2.66±0.07-2.82±0.02%). Statistically significant differences (p<0.05) were recorded among different milk brands for all physicochemical parameters except specific gravity. The highest and lowest amounts of total bacterial counts were 1150400 and 35500 CFU/ml, respectively. A significant difference (p<0.05) was found in bacterial loads among different brands of pasteurized milk. Conclusion: This survey revealed that different brands of Bangladeshi pasteurized milk did not maintain the standard and acceptable quality.
23 April 2023 in Turkish Journal of Agriculture - Food Science and Technology
This study was carried out to examine the prevalence of AFM1 contamination across different areas of Chattogram, Bangladesh, and to assess the level of AFM1 in raw milk samples from various dairy farms. A cross-sectional study was conducted to assess the farming standards of three different Chattogram neighborhoods—Bakalia, Khulshi, and Pahartali—and to ascertain the amount of AFM1 in milk. In the study location, 30 commercial dairy farms were randomly chosen, and data on farming methods, milk production techniques, and knowledge of aflatoxin contamination were gathered. Using the enzyme-linked immunosorbent assay (ELISA) method, collected milk samples (n = 90) were examined for the presence of AFM1. The farms produced 71.67±14.71 liters of milk on average every day, which was primarily supplied to dairy processing plants. For feeding the cows, all farms used concentrates and forage. The mean concentration of AFM1 in milk samples collected from Bakalia was higher (190.00±120.87 ng/L) than that in milk samples collected from the Khulshi (108.44±66.19 ng/L) and Pahartali (189.25±160.78 ng/L). The overall prevalence of AFM1 was 43% (N=39) of the total examined samples. A total of 69% (N=27) and 5% (N=2) of AFM1 positive samples exceeded the European Union Regulation (50 ng/L) and BSTI/BFSA regulations (500 ng/L) respectively. There was a significant difference in the occurrence of AFM1 in Bakalia regarding Khulshi and Pahartali. This research will aid in measuring the AFM1 content in raw milk and helping to address public health issues.
Keropok lekor a fish-based sausage is a popular traditional food item in Terengganu state, Malaysia. This study aimed to develop a new flavor and taste of keropok lekor. Common spices such as cumin, coriander, cinnamon, cardamom, bay leaf, nutmeg, clove, onion, ginger, garlic were used to develop a new flavor of keropok lekor. A total of 5 samples, including two original and three developed keropok lekor samples were prepared. This study also evaluated the proximate composition of two raw samples (Original and developed). The results of the proximate analysis showed a significant difference (p<0.05) in all parameters except the fiber content. Hardness, springiness, and chewiness of the samples were measured by using TA-XTplus texture analyzer. There was a significant difference in the hardness level between original and developed sample. Finally, sensory evaluation according to six attributes such as color, odors, texture, flavor, taste and overall acceptability was done by 39 panelists. A 7-point hedonic scale ranging from “dislike very much” to “like very much” was employed in sensory testing. There was a significant difference (p<0.05) in all the sensory parameters evaluated. The results showed that most of the respondents preferred the developed samples over the original samples. Developed fried keropok lekor with bread crumb was the most acceptable one.