Effects of disrupting the polyketide synthase gene WdPKS1 in Wangiella [Exophiala] dermatitidis on melanin production and resistance to killing by antifungal compounds, enzymatic degradation, and extremes in temperature

BACKGROUND: Wangiella dermatitidis is a human pathogenic fungus that is an etiologic agent of phaeohyphomycosis. W. dermatitidis produces a black pigment that has been identified as a dihydroxynaphthalene melanin and the production of this pigment is associated with its virulence. Cell wall pigmentation in W. dermatitidis depends on the WdPKS1 gene, which encodes a polyketide synthase required for generating the key precursor for dihydroxynaphthalene melanin biosynthesis. RESULTS: We analyzed the effects of disrupting WdPKS1 on dihydroxynaphthalene melanin production and resistance to antifungal compounds. Transmission electron microscopy revealed that wdpks1Δ-1 yeast had thinner cell walls that lacked an electron-opaque layer compared to wild-type cells. However, digestion of the wdpks1Δ-1 yeast revealed small black particles that were consistent with a melanin-like compound, because they were acid-resistant, reacted with melanin-binding antibody, and demonstrated a free radical signature by electron spin resonance analysis. Despite lacking the WdPKS1 gene, the mutant yeast were capable of catalyzing the formation of melanin from L-3,4-dihyroxyphenylalanine. The wdpks1Δ-1 cells were significantly more susceptible to killing by voriconazole, amphotericin B, NP-1 [a microbicidal peptide], heat and cold, and lysing enzymes than the heavily melanized parental or complemented strains. CONCLUSION: In summary, W. dermatitidis makes WdPKS-dependent and -independent melanins, and the WdPKS1-dependent deposition of melanin in the cell wall confers protection against antifungal agents and environmental stresses. The biological role of the WdPKS-independent melanin remains unclear

Prevalence of Candida glabrata and its response to boric acid vaginal suppositories in comparison with oral fluconazole in patients with diabetes and vulvovaginal candidiasis

Objective: A large proportion of vulvovaginal candidiasis (VVC) in diabetes is due to non-albicans Candida species such as C. glabrata and C. tropicalis. Observational studies indicate that diabetic patients with C. glabrata VVC respond poorly to azole drugs. We evaluated the response to oral fluconazole and boric acid vaginal suppositories in diabetic patients with VVC. Research Design And Methods: A total of 112 consecutive diabetic patients with VVC were block randomized to receive either single-dose oral 150-mg fluconazole or boric acid vaginal suppositories (600 mg/day for 14 days). The primary efficacy outcome was the mycological cure in patients with C. glabrata VVC in the two treatment arms. The secondary outcomes were the mycological cure in C. albicans VVC, overall mycological cure irrespective of the type of Candida species, frequencies of yeast on direct microscopy, and clinical symptoms and signs of VVC on the 15th day of treatment. Intention-to-treat (ITT; n = 111) and per-protocol (PP; n = 99) analyses were performed. Results: C. glabrata was isolated in 68 (61.3%) and C. albicans in 32 (28.8%) of 111 subjects. Patients with C. glabrata VVC showed higher mycological cure with boric acid compared with fluconazole in the ITT (21 of 33, 63.6% vs. 10 of 35, 28.6%; P = 0.01) and PP analyses (21 of 29, 72.4% vs. 10 of 30, 33.3%; P = 0.01). The secondary efficacy outcomes were not significantly different in the two treatment arms in the ITT and PP analyses. Conclusions: Diabetic women with C. glabrata VVC show higher mycological cure with boric acid vaginal suppositories given for 14 days in comparison with single-dose oral 150-mg fluconazole

Preventive strategies for substance use

Drug use among adolescents is on the rise, posing a great challenge to the health-care providers. The above concerns have led to recent research initiatives aiming at the development of preventive interventions for adolescents. This review gives an overview of such initiatives which target at reducing modifiable risk factors and enhancing protective factors through family, school, and community prevention programs

A classical case of bulimia nervosa from India

A classic case of the bulimia nervosa in a young Indian female is reported. This is in the context of the impression that due to increasing western influence, and change in cultural concepts of beauty and thinness among women, illnesses previously considered rare in Indian subcontinent might be becoming more prevalent. Many of the established pre-disposing factors such as female gender, metropolitan domicile, family history of depressive disorder have conglomerated in this case. Rapid and sustained improvement with the low-dose Fluoxetine and the Cognitive Behavioral Therapy is also worth paid attention

CHIKUNGUNYA, SCRUB TYPHUS MONO, AND CO-INFECTION AMONG PATIENTS WITH UNDIFFERENTIATED FEBRILE ILLNESS: A HOSPITAL-BASED STUDY

Objectives: Chikungunya virus is a common arthropod-related acute febrile disease and it is transmitted by Aedes aegypti or Aedes albopictus species. On the other hand, the bacterium Orientia tsutsugamushi causes scrub typhus, which is also an acute febrile illness with multiple organ involvement. Coinfection of chikungunya and scrub typhus may lead to severe manifestation including severe respiratory and central nervous system (CNS) complications. Coinfection of chikungunya and scrub typhus may lead to severe manifestation including severe respiratory and CNS complications. Therefore, the proper diagnosis can prevent the clinical complications. The aim and objective of our study is to find the seroprevalence of chikungunya and scrub typhus and coinfection of both through medical assessment and serological research of these patients presented with acute febrile infection at Diamond Harbour Government Medical College and Hospital. Methods: A prospective study was conducted from August 2022 to January 2023 at VRDL, Department of Microbiology, Diamond Harbour Government Medical College and Hospital. Serum was collected for IgM antibody enzyme-linked immunosorbent assay (ELISA) for scrub typhus (In bios kit) and Chikungunya (NIV Chikungunya IgM Capture ELISA Kit) test. Four hundred and eighty-seven samples were tested for IgM antibody by chikungunya and scrub typhus ELISA kit. Result: The present study demonstrated that, from the month of August 2022 to January 2023, 67% of chikungunya cases, 25% cases with only scrub typhus, and 8% cases with both chikungunya and scrub typhus presented positive. A present study shows that chikungunya is slightly more prevalent in males as compared to females, where scrub typhus is equally positive in both male and female patients. Conclusion: Laboratory testing of both of the diseases can prevent the complication of other suspected disease in coinfected patients

Dual growth factor loaded nonmulberry silk fibroin/carbon nanofiber composite 3D scaffolds for in vitro and in vivo bone regeneration

In recent years the potential application of nanocomposite biomaterials in tissue engineering field is gaining importance because of the combined features of all the individual components. A bottom-up approach is acquired in this study to recreate the bone microenvironment. The regenerated silk protein fibroin obtained from nonmulberry tropical tasar Antheraea mylitta species is reinforced with functionalized Carbon Nano Fiber (CNF) and the composite sponges are fabricated using facile green aqueous based method. Biophysical investigations show that the matrices are porous and simultaneously bioactive when incubated in simulated body fluid. The reinforcement of CNF influences the mechanical property of the matrices by increasing the compressive modulus up to 46.54 MPa (∼4.3 times of the control fibroin sponge) in hydrated state, which is higher than the minimum required human trabecular bone modulus (10 MPa). The composite matrices are found to be non-hemolytic as well as cytocompatible. The growth factors (BMP-2 and TGF-β1) loaded composites show sustained release kinetics and an early attachment, growth, proliferation and osteogenic differentiation of the osteoblasts and mesenchymal stem cells. The matrices are immunocompatible as evidenced by minimal release of pro-inflammatory cytokines both in vitro and in vivo. In order to support the in vitro study, in vivo analysis of new bone formation within the implants is performed through radiological, μ-CT, fluorochrome labeling and histological analysis, which show statistically better bone formation on growth factor loaded composite scaffolds. The study clearly shows the potential attributes of these composite matrices as an extra cellular matrix for supporting successful osseointegration process