Laboratory Culture Research Articles

Vaginal candidiasis, predisposing factors, symptoms and treatment

Introduction: Vulvovaginal candidiasis is a disease caused by Candida species, mainly Candida albicans species, which can be colonizing the vaginal microbiota of healthy women, without causing disease. Due to its high prevalence, it is one of the most frequent causes of gynecological consultation. It occurs mainly in women after puberty, worldwide it is estimated that at least 75% of women have had candidiasis at least once in their lives. Its clinical signs are itching, vaginal inflammation and white discharge. It is diagnosed by laboratory tests or culture. A higher frequency of candidiasis occurs in women with high estrogen load or some degree of immunodeficiency. Treatment consists of azole antifungals, particularly fluconazole. The present study consists of a systematic review of the existing literature related to vulvovaginal candidiasis, focusing on epidemiology, clinical signs, diagnosis and treatment. Material and methods: The study design is a literature review for which a search and evaluation of the existing literature and previous research on vaginal candidiasis will be carried out through the databases PubMed, Google Academic, Scielo, Sciendirect, among others. For this purpose, inclusion criteria will be used through searches related to "Candida", "vaginal candidiasis", "recurrent vaginal candidiasis", "vaginal candidiasis predisposing factors" and "candidiasis literature review". Results: Vaginal candidiasis is an infection caused by the overgrowth of Candida albicans, a type of yeast-like fungus that normally lives in the vagina. Predisposing factors include antibiotic use, increased estrogen levels, uncontrolled diabetes, overweight, pregnancy, premenstrual period, taking corticosteroids, and high doses of estrogen. Treatment of vaginal candidiasis includes antifungal medications, such as single-dose oral fluconazole, and avoidance of excess moisture. In uncomplicated vulvovaginal candidiasis, all available forms of antifungals are highly effective, both oral and topical, whereas in complicated vulvovaginal candidiasis, a longer course of 5-7 to 10-14 days of conventional therapy should be performed. Patients who have frequent recurrences require their long-term pressure with oral medications. Conclusion: It is important for health care professionals and patients to be aware of the risks of recurrence so that timely treatment can be provided to patients

Notes on the experimental laboratory and field culture of Lessonia variegata (Laminariales)

ABSTRACT The kelp Lessonia variegata J. Agardh (Lessoniaceae) is a potential aquaculture target for bioactive compounds. We investigated the control and management of Lessonia gametogenesis, the settlement and retention of sporophytes on various culture strings, and the upscaling of string settlement for field trials. In the laboratory we held gametophytes at low light conditions for 2.5 months before altering conditions to stimulate them into the next part of the life cycle. Settlement and development of sporophytes was highest on Korean culture string, followed by Builders Line, however after agitation, fewer sporophytes were dislodged from the Builders Line. Larger scale settlement of spores onto 15 m lengths of Builders Line was successful, with sporophytes reaching ∼5 mm length in 46 days. Eight weeks after out-planting, the sporophytes were heavily fouled with other algae. Although the results presented here were small-scale and lack replication, they add to the existing knowledge on the biology and cultivation of this species.

Different light intensity on Messastrum gracile growth under phototrophic cultivation in laboratory.

The present research evaluates the effects of three different lighting intensities, 60 (control), 30 and 120 µmol photons m- 2 s- 1 on Messastrum gracile growth. The observations indicated that a light intensity of 60 µmol photons m- 2 s- 1 resulted in higher cell density during experimental period. The light intensity of 120 µmol photons m- 2 s- 1 had a strong negative impact on M. gracile growth. Parameters such as lipid and protein content, cell density, chlorophyll-a and biomass were lower compared to the other light intensities. On the 14th and 21st growth days, the biomass, lipid and protein content were higher at 60 µmol photons m- 2 s- 1 with 800 mg L- 1, 5.7% and 34.4% biomass dry weight, respectively. The study also highlighted the economic aspects of M. gracile cultivation. The light intensities 30 and 60 µmol photons m- 2 s- 1 were found to be more advantageous than 120 µmol photons m- 2 s- 1 in terms of biomass, unit cost, lipid and protein content. Based on these findings, it was concluded that the light intensities of 30 and 60 µmol photons m- 2 s- 1 are more viable for M. gracile cultivation in laboratory under conditions used.

Characterization of Springtail (Arrhopalites caecus) for Use in Soil Ecotoxicity Testing.

Springtails (subclass: Collembola) represent one of the most extensively studied invertebrate groups in soil ecotoxicology. This is because of their ease of laboratory culture, significant ecological role, and sensitivity to environmental contaminants. Folsomia candida (family: Isotomidae) is a globally widespread parthenogenetic species that is prevalent in laboratory toxicity testing with springtails. Conversely, Arrhopalites caecus (family: Arrhopalitidae), a parthenogenic globular springtail species, remains untested in soil ecotoxicology. This species is found in diverse habitats, including cave systems and forest leaf litter, and has a global distribution. The sensitivity of A. caecus to environmental contaminants, such as neonicotinoid insecticides, as well as its life history and optimal culturing conditions, are largely unknown. The present study describes the establishment of a pure A. caecus laboratory culture and characterization of its life cycle and culturing conditions. We assessed the sensitivity of A. caecus to various insecticides, including exposures to the neonicotinoid thiamethoxam in soil and through a novel feeding assay as well as to clothianidin and cyantraniliprole in spiked soil exposures. In 7- and 14-day exposures to thiamethoxam in agricultural soil, the 50% lethal concentration (LC50) values were determined to be 0.129 mg/kg dry weight and 0.010 mg/kg dry weight, respectively. The 14-day LC50 for exposure to thiamethoxam via spiked food was determined to be 0.307 mg/kg dry weight. In addition, the 28-day 50% effect concentration for inhibition of juvenile production from cyantraniliprole exposure in the same soil type was 0.055 mg/kg dry weight. Challenges encountered in using this species included susceptibility to mite infestation and low adult survival rates in the 28-day cyantraniliprole test. Environ Toxicol Chem 2024;43:1820-1835. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Insertion site and risk of peripheral intravenous catheter colonization and/or local infection: a post hoc analysis of the CLEAN 3 study including more than 800 catheters

AimAlthough uncommon, infections associated with peripheral intravenous catheters (PIVCs) may be responsible for severe life-threatening complications and increase healthcare costs. Few data are available on the relationship between PIVC insertion site and risk of infectious complications.MethodsWe performed a post hoc analysis of the CLEAN 3 database, a randomized 2 × 2 factorial study comparing two skin disinfection procedures (2% chlorhexidine-alcohol or 5% povidone iodine-alcohol) and two types of medical devices (innovative or standard) in 989 adults patients requiring PIVC insertion before admission to a medical ward. Insertion sites were grouped into five areas: hand, wrist, forearm, cubital fossa and upper arm. We evaluated the risk of risk of PIVC colonization (i.e., tip culture eluate in broth showing at least one microorganism in a concentration of at least 1000 Colony Forming Units per mL) and/or local infection (i.e., organisms growing from purulent discharge at PIVC insertion site with no evidence of associated bloodstream infection), and the risk of positive PIVC tip culture (i.e., PIVC-tip culture eluate in broth showing at least one microorganism regardless of its amount) using multivariate Cox models.ResultsEight hundred twenty three PIVCs with known insertion site and sent to the laboratory for quantitative culture were included. After adjustment for confounding factors, PIVC insertion at the cubital fossa or wrist was associated with increased risk of PIVC colonization and/or local infection (HR [95% CI], 1.64 [0.92—2.93] and 2.11 [1.08—4.13]) and of positive PIVC tip culture (HR [95% CI], 1.49 [1.02—2.18] and 1.59 [0.98—2.59]).ConclusionPIVC insertion at the wrist or cubital fossa should be avoided whenever possible to reduce the risk of catheter colonization and/or local infection and of positive PIVC tip culture.

Isolation And Diagnosis Of Skin Fungi That Causes Tinea Capitis In The Children

One hundred clinical samples of hair and scalp flakes were collected for children with tinea capitis aged from 1 year to 12 years from the dermatology consultant affiliated with Tikrit Teaching Hospital and outpatient clinics, with the aim of isolating the pathogenic fungi that cause tinea capitis and diagnosing them in children. Out of the total, 77 samples were found in the laboratory culture, while the findings of the direct microscopic examination indicated the presence of 55 samples. Several dermatophyte species from the genera Trichophyton and Microsporum were identified. T. mentagrophytes was the most prevalent with 18 isolates (23%), followed by T. violaceum and T. rubrum, each with 12 isolates (15%). Next, there were 10 isolates of the fungus T. schoenleinii (13%), compared to 4 isolates (10%) of each of the two species of fungus, T. tonsurans and T. verrucosum. While fungi belonging to the genus Microsporum were isolated at a rate of 10 isolates (13%) of the type M. canis, while 7 isolates of the M. gypsum type were isolated (9%). The incidence of tinea capitis among was greater in men than in women., as the number of infected males was 62 (62%), and females were 38 (38%) infected out of the total number. Regarding age groupings, 20% of children between the ages of one and four have head ringworm. The infection rate for children aged 5-8 was 32%, and the highest risk of infection was for those aged 9-12, who were at risk for 48%. It was also found that the rate of infection with the fungi that cause tinea capitis in the children from whom the samples were taken was high among patients coming from rural areas, at 80%, compared to patients coming from urban areas, at 20%.

Salinity decline promotes growth and harmful blooms of a toxic alga by diverting carbon flow.

Global climate change intensifies the water cycle and makes freshest waters become fresher and vice-versa. But how this change impacts phytoplankton in coastal, particularly harmful algal blooms (HABs), remains poorly understood. Here, we monitored a coastal bay for a decade and found a significant correlation between salinity decline and the increase of Karenia mikimotoi blooms. To examine the physiological linkage between salinity decreases and K. mikimotoi blooms, we compare chemical, physiological and multi-omic profiles of this species in laboratory cultures under high (33) and low (25) salinities. Under low salinity, photosynthetic efficiency and capacity as well as growth rate and cellular protein content were significantly higher than that under high salinity. More strikingly, the omics data show that low salinity activated the glyoxylate shunt to bypass the decarboxylation reaction in the tricarboxylic acid cycle, hence redirecting carbon from CO2 release to biosynthesis. Furthermore, the enhanced glyoxylate cycle could promote hydrogen peroxide metabolism, consistent with the detected decrease in reactive oxygen species. These findings suggest that salinity declines can reprogram metabolism to enhance cell proliferation, thus promoting bloom formation in HAB species like K. mikimotoi, which has important ecological implications for future climate-driven salinity declines in the coastal ocean with respect to HAB outbreaks.

Combining the Elicitor Up-Regulated Production of Unusual Linear Diterpene-Derived Variants for an In-Depth Assessment of the Application Value and Risk of the Medicinal and Edible Basidiomycete Schizophyllum commune.

To better assess the practical value and avoid potential risks of the traditionally medicinal and edible basidiomycete Schizophyllum commune, which may arise from undescribed metabolites, a combination of elicitors was introduced for the first time to discover products from cryptic and low-expressed gene clusters under laboratory cultivation. Treating S. commune NJFU21 with the combination of five elicitors led to the upregulated production of a class of unusual linear diterpene-derived variants, including eleven new ones (1-11), along with three known ones (12-14). The structures and stereochemistry were determined by 1D and 2D NMR, HRESIMS, ECD, OR and VCD calculations. Notably, the elongation terminus of all the diterpenes was decorated by an unusual butenedioic acid moiety. Compound 1 was a rare monocyclic diterpene, while 2-6 possessed a tetrahydrofuran moiety. The truncated metabolites 4, 5 and 13 belong to the trinorditerpenes. All the diterpenes displayed approximately 70% scavenging of hydroxyl radicals at 50 μM and null cytotoxic activity at 10 μM. In addition, compound 1 exhibited potent antifungal activity against the plant pathogenic fungi Colletotrichum camelliae, with MIC values of 8 μg/mL. Our findings indicated that this class of diterpenes could provide valuable protectants for cosmetic ingredients and the lead compounds for agricultural fungicide development.

Clinical perspectives on sampling and processing approaches for the management of infection in diabetic foot ulceration: A qualitative study.

Diabetic foot ulcers (DFUs) often become infected and are treated with antimicrobials, with samples collected to inform care. Swab samples are easier than tissue sampling but report fewer organisms. Compared with culture and sensitivity (C&S) methods, molecular microbiology identifies more organisms. Clinician perspectives on sampling and processing are unknown. We explored clinician perspectives on DFU sampling-tissue samples/wound swabs-and on processing techniques, culture and sensitivity or molecular techniques. The latter provides information on organisms which have not survived transport to the laboratory for culture. We solicited feedback on molecular microbiology reports. Qualitative study using semi-structured interview, with analysis using a Framework approach. CODIFI2 clinicians from UK DFU clinics. Seven consultants agreed to take part. They reported, overall, a preference for tissue samples over swabbing. Clinicians were not confident replacing C&S with molecular microbiology as the approach to reporting was unfamiliar. The study was small and did not recruit any podiatrists or nurses, who may have discipline-specific attitudes or perspectives on DFU care. Both sampling approaches appear to be used by clinicians. Molecular microbiology reports would not be, at present, suitable for replacement of traditional culture and sensitivity.

Response of inner shelf benthic foraminiferal community to different concentrations of dissolved oxygen under laboratory culture experiment

Dissolved oxygen, a vital parameter for a majority of marine organisms, may decline in the near future due to anthropogenic eutrophication in coastal waters. The effect of depleting dissolved oxygen on the marine benthic community is difficult to assess from field studies, as dissolved oxygen often co-varies with several other parameters, especially organic matter. The controlled laboratory culture experiments can help to assess the effect of a specific parameter on marine organisms. Foraminifera constitute a substantial fraction of the marine benthic organisms, and a few species are vulnerable to depleted oxygen. A majority of the previous culture experiments have used isolated specimens of individual benthic foraminiferal species. Although such studies helped to understand the response of individual species to a particular parameter, they have to be scaled up to understand the community-level response of benthic foraminifera. Here, we assess the community-level response of the shallow subtidal benthic foraminiferal community to five different oxygen concentrations (1.67 mL/L to 5.01 mL/L) in a laboratory culture experiment. The living benthic foraminiferal abundance was considerably high at the intermediate oxygen concentration, whereas it decreased at both the lower and higher concentrations. The decreasing dissolved oxygen caused poor preservation of dead benthic foraminifera due to a drop in pH. The relative abundance trend of the species belonging to the same genus was different, suggesting a species-specific response to the dissolved oxygen. The maximum abundance at 2.91 mL/L and the varying response of individual species clearly suggest a non-linear response of the benthic foraminiferal community to the dissolved oxygen.

Isolation and evaluation of local microalgal isolates as feed for larval rearing of Crassostrea tulipa towards optimisation of mangrove oyster seed production in Ghana

AbstractThis study explored the potential of three local microalgal isolates as feed for oyster larvae in laboratory‐rearing experiments, towards the optimisation of seed production of Crassostrea tulipa to support its large‐scale farming along the West African coast. Three species of local microalgae—Rhodomonas sp., Nannochloropsis sp. and Pseudanabaena sp.—were isolated from waters off the coast of Ghana, West Africa, following a serial dilution technique. The growth performance of the isolates was assessed in the laboratory through daily estimation of cell density until the stationary phase was observed. Characterisation of the microalgal isolates was carried out by estimation of their biovolume, carbon content and energy content. Biovolumes of the microalgae were calculated from the estimated equivalent spherical diameters using proposed geometric shapes and formulae. Carbon weight and carbon energy content were subsequently calculated using derived conversions. The three microalgal isolates showed potential for large‐scale cultivation in the laboratory with marked differences in daily increases in cell densities. Nannochloropsis sp. and Rhodomonas sp. recorded the highest and the lowest peak densities of 2.4 × 105 and 1.5 × 105 cell mL−1, respectively, from an initial inoculating cell density of 1.05 × 105 cell mL−1. The estimated mean biovolumes of Rhodomonas sp., Nannochloropsis sp. and Pseudanabaena sp. were 238.9, 8.182 and 42.42 µm3, respectively, and the corresponding derived carbon energy contents were 1.7 × 10−6, 7.13 × 10−8 and 1.05 × 10−7 J, respectively. Results from a laboratory rearing experiment indicated that the individual microalgal isolates supported the growth and survival of oyster larvae at different scales, but a mixed diet of the three promoted superior growth and survival of C. tulipa larvae. The three local microalgal isolates‐ Rhodomonas sp., Nannochloropsis sp., and Pseudanabaena sp.‐ were well adapted to laboratory culture conditions, and the observed differences in growth and survival of the oyster larvae fed on these algal diets could be due to the differences in diet properties and biochemical compositions of the different species. A combination of the three algal diets, however, provided complementaery nutrients for the optimal growth and survival of C. tulipa larvae. The outcome of this study shows that local microalgal isolates have the potential to support hatchery rearing of C. tulipa, which is essential for the development of commercial mangrove oyster aquaculture in West Africa.

Prevalence of Candida albicans Infection Among Diabetic Foot Ulcer Patients in Al-Yarmouk Teaching Hospital

Abstract Objectives: The current study aims to investigate “Candida albicans” in diabetic foot ulcer (DFU) infections in Baghdad. Materials and Methods: Clinical samples were collected from 203 patients with DFUs treated at Al-Yarmouk Teaching Hospital and outpatient clinic. There were 105 male and 98 female participants. The study period was from December 15, 2021 to May 15, 2022. Results: The mean age was 56.50 years, and 132 (65%) of the patients were aged between 46 and 65 years. The average diabetes duration was 10.96 ± 4.63 years, and 108 (53.2%) of the patients had a history of diabetic mellitus (DM) for 3–10 years. Out of the 203 clinical samples, 113 (56%) were positive for fungal growth. Cultural characteristics and biochemical criteria revealed that 66 (58.4%) isolates out of the 113 were different types of Candida, including C. tropicalis, C. krusei, C. parapsilosis, C. lipolytica, C. lusitaniae, and C.guilliermondii. The results showed that 15 (13.2%) isolates were C. albicans, with a higher percentage in females compared to males (40%). Among the age groups, the 46–65 age group showed 53.3% of C. albicans. The time period of diabetes (3–10 years) was the highest rate of C. albicans emergence. Conclusion: The current study concludes that fungal infections, including Candida species, are common among patients with diabetic foot diseases. Regular laboratory culturing of the fungal swabs is necessary for periodic diagnosis in order to monitor and control fungal diseases associated with diabetic foot infections.

Indirect shoot regeneration from callus of the shoot tip explants of Gerbera jamesonii Bolus cv. "Festival"

The study was conducted in the Tissue Culture Laboratory, Fadak Agricultural Company, Basrah, Iraq. Mother plants of the “Festival” gerbera cultivar were used for micropropagation by taking the shoot tip explants. The concentration of 2 mgL-1 benzyl adenine (BA) resulted in recording the highest percentage of response to callus induction, reaching 90%, which was significantly superior to the other two treatments, 1 and 1.5mgL-1 BA. The 1 mgL-1 BA treatment was significantly superior in response to indirect shoot generation when compared with the 1.5 and 2 mgL-1 BA treatments. The 1 mgL-1 BA treatment recorded the highest percentage of response to shoot growth induced by callus, which reached 100%. The treatment of callus grown in MS medium supplied with BA concentration of 1 mgL-1 recorded the highest average number of shoots, which reached 10 shoots per 50 mg of callus. The MS medium treatment supplied with a concentration of 0.5 mgL-1 of naphthalene acetic acid (NAA) was significantly superior to the other two treatments of 1 and 1.5 mgL-1 NAA in the percentage of shoot response to root formation. The concentration of 0.5mgL-1 NAA recorded the highest response to root formation, which reached 100%. The treatment of the MS medium supplied with a concentration of 0.5 mgL-1 NAA was significantly superior to the treatments of 1 and 1.5 mgL-1 NAA in the average number of main roots formed on the shoots. This treatment recorded the highest average of main roots, amounting to 3.2 main roots shoot-1. Callus, cultivar, indirect shoot, micropropagation, proliferation, MS salts.

Culture of Cultures: A Small Step Towards Augmenting Diagnostic Stewardship.

Laboratories with a well-established diagnostic stewardship program for culture and the antimicrobial susceptibility test (C-AST) play a key role in guiding clinicians to institute specific targeted therapy. Blood culture is one of the most critical investigations performed at a microbiology laboratory. Therefore, it is particularly important to develop a robust diagnostic stewardship model for the blood culture laboratory division. Aiming at this hypothesis, this hospital-based clinical audit carried out within the Department of General Medicine, centered on the critical domain of antimicrobial stewardship (AMSP). The audit's primary objective was to systematically evaluate prevailing practices and pinpoint areas necessitating refinement in the administration of antimicrobial agents. Employing a meticulous approach involving exhaustive data scrutiny and feedback mechanisms, the audit unearthed strategic opportunities to optimize prescription patterns, curtail unwarranted antimicrobial utilization, and fortify adherence to established guidelines. The subsequent execution of targeted interventions, encompassing educational initiatives and routine performance feedback, culminated in a noteworthy enhancement of antimicrobial prescribing practices. These outcomes unequivocally underscore the efficacy of the audit in cultivating a milieu of judicious antimicrobial utilization, thereby augmenting patient care and mitigating antibiotic resistance within the department.

Religion as a natural laboratory for understanding human behavior

What do we gain from the scientific study of religion? One possibility is that religious contexts are unique, and cognition within these contexts is worth understanding. Another possibility is that religion can be viewed as a laboratory for understanding psychology and culture more broadly. Rather than limiting the study of religion to a single context, I argue that the study of religion is useful precisely because it illuminates secular psychological and cultural processes. I first outline my practical approach to psychology and religion, focusing on how people use religion to advance mundane goals. I then discuss several domains in which studying religion has led to important insights, including culture, prejudice, and cognition. This article is an extended version of an Early Career Award address given at the International Association for the Psychology of Religion meeting in 2023 in Groningen, Netherlands.

Callus formation response from immature male flower explant of plantain banana (Musa acuminata x Musa balbisiana cv. Kepok) treated by 2,4-D and BAP

Callus induction is an important step in indirect somatic embryogenesis. The aim of this study was to obtain an optimal medium for the callus formation of plantain bananas (cv. Kepok). The research was conducted from May to August 2022 at the Tissue Culture Laboratory of PT. ITCI Kartika Utama, Penajam Paser Utara District, East Kalimantan. The explant used an immature male flower of plantain banana (cv. Kepok). The experiment used a completely randomized design with two factors concentration of 2,4-D (1,2 and 4 ppm) and BAP (5, 10, and 15 ppm). The appearance of callus was monitored daily until it developed explants. On the final observation day, the percentage of explants with callus, as well as the color and texture of the callus, were assessed. The research findings suggest that the optimal medium for inducing callus in male banana flower explants was MS medium supplemented with 2 ppm 2,4-D and 5 ppm BAP. This medium resulted in calluses that exhibited a yellowish-white color and a compact texture. Keywords: callus morphology; genetic improvement; plant growth regulator; tissue culture; triploid banana

Pathogen-microbiome interactions and the virulence of an entomopathogenic fungus.

Entomopathogenic fungi play important roles in the population dynamics of many insect species. Understanding the factors shaping entomopathogen virulence is critical for agricultural management and for the use of fungi in pest biocontrol. We show that heritable bacteria in aphids, which confer protection to their hosts against fungal entomopathogens, influence virulence against subsequent hosts. Aphids reproduce asexually and are typically surrounded by genetically identical offspring, and thus these effects likely shape the dynamics of fungal disease in aphid populations. Furthermore, fungal entomopathogens are known to rapidly lose virulence in lab culture, complicating their laboratory use. We show that this phenomenon is not driven by changes in the associated bacterial microbiome. These results contribute to our broader understanding of the aphid model system and shed light on the biology of the Entomophthorales-an important but understudied group of fungi.

Biotechnological potential of actinomycetes in the 21st century: a brief review.

This brief review aims to draw attention to the biotechnological potential of actinomycetes. Their main uses as sources of antibiotics and in agriculture would be enough not to neglect them; however, as we will see, their biotechnological application is much broader. Far from intending to exhaust this issue, we present a short survey of the research involving actinomycetes and their applications published in the last 23years. We highlight a perspective for the discovery of new active ingredients or new applications for the known metabolites of these microorganisms that, for approximately 80years, since the discovery of streptomycin, have been the main source of antibiotics. Based on the collected data, we organize the text to show how the cosmopolitanism of actinomycetes and the evolutionary biotic and abiotic ecological relationships of actinomycetes translate into the expression of metabolites in the environment and the richness of biosynthetic gene clusters, many of which remain silenced in traditional laboratory cultures. We also present the main strategies used in the twenty-first century to promote the expression of these silenced genes and obtain new secondary metabolites from known or new strains. Many of these metabolites have biological activities relevant to medicine, agriculture, and biotechnology industries, including candidates for new drugs or drug models against infectious and non-infectious diseases. Below, we present significant examples of the antimicrobial spectrum of actinomycetes, which is the most commonly investigated and best known, as well as their non-antimicrobial spectrum, which is becoming better known and increasingly explored.

Validity of luminometry and bacteriological tests for diagnosing intramammary infection at dry-off in dairy cows

The objective of this cross-sectional study was to estimate the validity of laboratory culture, Petrifilm and Tri-Plate on-farm culture systems, and luminometry to correctly identify IMI at dry-off in dairy cows, considering all tests as imperfect. From September 2020 until December 2021, we collected composite milk samples from cows before dry-off and divided them into 4 aliquots for the luminometry test, the Petrifilm (aerobic count), the Tri-Plate, and the laboratory culture. While we assessed multiple thresholds of relative light units (RLU) for the luminometry, we used thresholds of ≥100 cfu/mL for the laboratory culture, ≥ 50 cfu/mL for the Petrifilm, and ≥1 cfu for the Tri-Plate. We fitted Bayesian latent class analysis (LCA) models to estimate the sensitivity (Se) and specificity (Sp) for each test to identify IMI, with 95% credibility interval (BCI). Using different prevalence measures (0.30, 0.50, and 0.70), we calculated the predictive values (PV) and misclassification cost terms (MCT) at different false-negative to false-positive ratios (FN:FP). A total of 333 cows were enrolled in the study from one commercial Holstein herd. The validity of the luminometry was poor for all thresholds, with Se of 0.51 (95% BCI = 0.43-0.59) and Sp of 0.38 (95% BCI = 0.26-0.50) when using a threshold of ≥150 RLU. The laboratory culture had Se of 0.93 (95% BCI = 0.85-0.98) and Sp of 0.69 (95% BCI = 0.49-0.89), the Petrifilm had Se of 0.91 (95% BCI = 0.80-0.98) and Sp of 0.71 (95% BCI = 0.51-0.90), and the Tri-Plate had Se of 0.65 (95% BCI = 0.53-0.82) and Sp of 0.85 (95% BCI = 0.66-0.97). Bacteriological tests had good PVs, with comparable positive PV for all 3 tests, but lower negative PV for the Tri-Plate compared with the laboratory culture and the Petrifilm. For a prevalence of IMI of 0.30, all 3 tests had similar MCT, but for prevalence of 0.50 and 0.70, the Tri-Plate had higher MCT in scenarios where leaving a cow with IMI untreated is considered to have greater detrimental impacts than treating a healthy cow (i.e., FN:FP of 3:1). Our results showed that the bacteriological tests have adequate validity to diagnose IMI at dry-off, but the luminometry does not. We concluded that, while luminometry is not useful to identify IMI at dry-off, the Petrifilm and Tri-Plate tests performed similarly to the laboratory culture, depending on the prevalence and the importance of the FP and FN results.

Optical sensor reveals the hidden influence of cell dissociation on adhesion measurements

Cell adhesion experiments are important in tissue engineering and for testing new biologically active surfaces, prostheses, and medical devices. Additionally, the initial state of adhesion (referred to as nascent adhesion) plays a key role and is currently being intensively researched. A critical step in handling all adherent cell types is their dissociation from their substrates for further processing. Various cell dissociation methods and reagents are used in most tissue culture laboratories (here, cell dissociation from the culture surface, cell harvesting, and cell detachment are used interchangeably). Typically, the dissociated cells are re-adhered for specific measurements or applications. However, the impact of the choice of dissociation method on cell adhesion in subsequent measurements, especially when comparing the adhesivity of various surfaces, is not well clarified. In this study, we demonstrate that the application of a label-free optical sensor can precisely quantify the effect of cell dissociation methods on cell adhesivity, both at the single-cell and population levels. The optical measurements allow for high-resolution monitoring of cellular adhesion without interfering with the physiological state of the cells. We found that the choice of reagent significantly alters cell adhesion on various surfaces. Our results clearly demonstrate that biological conclusions about cellular adhesion when comparing various surfaces are highly dependent on the employed dissociation method. Neglecting the choice of cellular dissociation can lead to misleading conclusions when evaluating cell adhesion data from various sources and comparing the adhesivity of two different surfaces (i.e., determining which surface is more or less adhesive).