Cheminformatics Identification and Validation of Dipeptidyl Peptidase-IV Modulators from Shikimate Pathway-Derived Phenolic Acids towards Interventive Type-2 Diabetes Therapy

Recently, dipeptidyl peptidase-IV (DPP-IV) has become an effective target in the management of type-2 diabetes mellitus (T2D). The study aimed to determine the efficacy of shikimate pathway-derived phenolic acids as potential DPP-IV modulators in the management of T2D. The study explored in silico (molecular docking and dynamics simulations) and in vitro (DPP-IV inhibitory and kinetics assays) approaches. Molecular docking findings revealed chlorogenic acid (CA) among the examined 22 phenolic acids with the highest negative binding energy (−9.0 kcal/mol) showing a greater affinity for DPP-IV relative to the standard, Diprotin A (−6.6 kcal/mol). The result was corroborated by MD simulation where it had a higher affinity (−27.58 kcal/mol) forming a more stable complex with DPP-IV than Diprotin A (−12.68 kcal/mol). These findings were consistent with in vitro investigation where it uncompetitively inhibited DPP-IV having a lower IC₅₀ (0.3 mg/mL) compared to Diprotin A (0.5 mg/mL). While CA showed promising results as a DPP-IV inhibitor, the findings from the study highlighted the significance of medicinal plants particularly shikimate-derived phenolic compounds as potential alternatives to synthetic drugs in the effective management of T2DM. Further studies, such as derivatisation for enhanced activity and in vivo evaluation are suggested to realize its full potential in T2D therapy.

Identification of Flavonoid C-Glycosides as Promising Antidiabetics Targeting Protein Tyrosine Phosphatase 1B

Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of the insulin signaling pathway, has gained attention as a validated druggable target in the management of type 2 diabetes mellitus (T2DM). The lack of clinically approved PTP1B inhibitors has continued to prompt research in plant-derived therapeutics possibly due to their relatively lesser toxicity profiles. Flavonoid C-glycosides are one of the plant-derived metabolites gaining increased relevance as antidiabetic agents, but their possible mechanism of action remains largely unknown. This study investigates the antidiabetic potential of flavonoid C-glycosides against PTP1B in silico and in vitro. Of the seven flavonoid C-glycosides docked against the enzyme, three compounds (apigenin, vitexin, and orientin) had the best affinity for the enzyme with a binding score of -7.3 kcal/mol each, relative to -7.4 kcal/mol for the reference standard, ursolic acid. A further probe (in terms of stability, flexibility, and compactness) of the complexes over a molecular dynamics time study of 100 ns for the three compounds suggested orientin as the most outstanding inhibitor of PTP1B owing to its overall -34.47 kcal/mol binding energy score compared to ursolic acid (-19.24 kcal/mol). This observation was in accordance with the in vitro evaluation result, where orientin had a half maximal inhibitory concentration (IC₅₀) of 0.18 mg/ml relative to 0.13 mg/ml for the reference standard. The kinetics of inhibition of PTP1B by orientin was mixed-type with V _max and K _m values of 0.004 μM/s and 0.515 μM. Put together, the results suggest orientin as a potential PTP1B inhibitor and could therefore be further explored in the management T2DM as a promising therapeutic agent.

Poultry gut health - microbiome functions, environmental impacts, microbiome engineering and advancements in characterization technologies

The gastrointestinal tract (GIT) health impacts animal productivity. The poultry microbiome has functions which range from protection against pathogens and nutrients production, to host immune system maturation. Fluctuations in the microbiome have also been linked to prevailing environmental conditions. Healthy poultry birds possess a natural resistance to infection. However, the exploration of environmental impacts and other relevant factors on poultry growth and health have been underplayed. Since good performance and growth rate are central to animal production, the host-microbiome relationship remains integral. Prior to the emergence of metagenomic techniques, conventional methods for poultry microbiome studies were used and were low-throughput and associated with insufficient genomic data and high cost of sequencing. Fortunately, the advent of high-throughput sequencing platforms have circumvented some of these shortfalls and paved the way for increased studies on the poultry gut microbiome diversity and functions. Here, we give an up-to-date review on the impact of varied environments on microbiome profile, as well as microbiome engineering and microbiome technology advancements. It is hoped that this paper will provide invaluable information that could guide and inspire further studies on the lingering pertinent questions about the poultry microbiome.

The burden of asymptomatic sexually transmitted infections among men in Carletonville, South Africa: implications for syndromic management

OBJECTIVES

To determine the prevalence of sexually transmitted infections (STI) and HIV among men attending an outreach STI/HIV screening service in informal settlements in South Africa over a 3-month period.

METHODS

A mobile clinic van was utilised to offer men: (1) urine screening for gonorrhoea, trichomoniasis, chlamydial and Mycoplasma genitalium infections; (2) serological screening for syphilis and herpes simplex virus type 2 (HSV-2); (3) on-site HIV voluntary counselling and testing. Urethritis pathogens were detected by molecular methods. HIV serostatus was determined using rapid tests. Demographic, sexual behaviour and clinical data were recorded on a nurse-administered questionnaire. Statistical analysis utilised the chi(2) test.

RESULTS

309 men attended the service; 304 (98%) requested serological screening for syphilis and HSV-2, 301 (97%) underwent urine-based screening for urethritis pathogens and 269 (87%) had an HIV test. Over 90% of men were asymptomatic for STI. Gonorrhoea was more prevalent in the symptomatic group (p<0.001); there were no significant differences in the prevalence of other urethritis pathogens between the groups. The total number of infections with each urethritis pathogen was highest in the asymptomatic group with twice as much gonorrhoea, 25 times as much chlamydial infection, six times as much trichomoniasis and nine times as much M genitalium infection compared with the symptomatic group. The overall HIV prevalence among clinic attendees was 29.7%.

CONCLUSIONS

The uptake of both STI and HIV testing was high among men attending the service. The relatively high burden of both STI and HIV among the male clinic attendees has implications for the transmission of HIV.

The detection of urethritis pathogens among patients with the male urethritis syndrome, genital ulcer syndrome and HIV voluntary counselling and testing clients: should South Africa's syndromic management approach be revised?

OBJECTIVES

To determine the prevalence of urethritis pathogens amongst male symptomatic urethritis (MUS) patients, genital ulcer (GUS) patients without urethritis symptoms and men requesting HIV testing at a voluntary counselling and testing (VCT) clinic.

METHODS

A prospective study was conducted in Johannesburg, South Africa. Men from the three groups were screened for urethritis pathogens using molecular tests. Culture for Neisseria gonorrhoeae and, initially, trichomoniasis was performed. Antimicrobial susceptibility testing was undertaken for ciprofloxacin on all gonococcal isolates; ciprofloxacin resistant isolates were screened for ceftriaxone resistance.

RESULTS

664 participants were recruited (438 MUS, 76 GUS and 158 VCT) over 2 years. Gonorrhoea was detected in 62.3% MUS, 15.8% GUS and 3.2% VCT participants. Chlamydial infection was detected in 19.3% MUS, 13.2% GUS and 8.2% VCT participants. Trichomoniasis was detected in 4.9% MUS, 19.7% GUS and 3.8% VCT participants. Mycoplasma genitalium infection was detected in 14.4% MUS, 13.2% GUS and 7.0% VCT participants. Ciprofloxacin resistance increased from 13.0% in the first year to 26.3% in the second year; all resistant isolates were susceptible to ceftriaxone.

CONCLUSIONS

Urethritis pathogens, including Trichomonas vaginalis, should be covered in syndromic management treatment of genital ulcers in the absence of clinical urethritis. Consideration should be given to adding metronidazole to existing MUS treatment. Ciprofloxacin can no longer be relied upon to treat presumptive gonococcal infections in South Africa.

Laboratory selection for and characteristics of pyrethroid resistance in the malaria vector Anopheles funestus

A laboratory colony of Anopheles funestus Giles (Diptera: Culicidae) was established in 2000 from material collected from southern Mozambique where pyrethroid resistance had been demonstrated in the wild population. A subsample of the colony was selected for pyrethroid resistance using 0.1% lambda-cyhalothrin. Bioassay susceptibility tests in subsequent generations F(2) to F(4) showed increased resistance with each successive generation. Survival of individual mosquitoes fed only on 10% sugar solution, increased with age up to 4 days, but by day 10 had decreased significantly. However, females that had been mated and given bloodmeals showed no such increase in mortality with age. Biochemical analysis of resistant and susceptible individuals showed increased monooxygenase and glutathione S-transferase activity but no significant correlation with age of the mosquitoes.

Evolution in the trends of antimicrobial resistance in Neisseria gonorrhoeae isolated in Durban over a 5 year period: impact of the introduction of syndromic management

Antimicrobial susceptibility testing was performed on isolates of Neisseria gonorrhoeae obtained from patients attending the City Health STD clinic in Durban, KwaZuluNatal, using the following drugs: penicillin, tetracycline, ciprofloxacin, ofloxacin, ceftriaxone, spectinomycin, erythromycin and azithromycin. These isolates were collected over a 6 year period from 1995 to 2000. Four hundred and fifteen strains were tested: 61 in 1995, 198 in 1997, 98 in 1998/99 and 58 in 1999/2000. A shift to the right is observed in the susceptibilities of N. gonorrhoeae to the currently recommended drugs in the syndromic management guidelines viz. penicillin, tetracycline, ceftriaxone, ciprofloxacin, spectinomycin and erythromycin. The prevalence of penicillinase-producing N. gonorrhoeae is currently c. 30%, whereas that of plasmid-mediated tetracycline-resistant N. gonorrhoeae is c. 50%. There is a definite association between the MICs of strains falling within the penicillin and tetracycline chromosomally resistant group, and strains exhibiting a decreased susceptibility to ciprofloxacin and ceftriaxone. The MICs of azithromycin showed a similar distribution when compared with erythromycin for 1999/2000 isolates. We postulate that the presence of efflux pumps might play a role in the increasing MICs that we observe among structurally unrelated groups of drugs. Furthermore, widespread use of these antimicrobials in the community may offer a selective advantage to the development of resistance. The implications of this are far reaching and the local susceptibility trends of N. gonorrhoeae need to be monitored constantly to direct therapy.

HIV-1 drug resistance and mother-to-child transmission

The use of antiretroviral drug therapies in HIV-1 infected pregnant women and their infants has resulted in significant reductions in the rates of mother-to-child transmission of HIV-1. A number of drugs that target the reverse transcriptase enzyme have been tested either alone or in combination in short-course regimens tailored for use in developing countries. The drug of choice is nevirapine, which is cheap, easy to administer and highly effective even following a single dose to mother and child. However, this regimen is associated with the selection of mutations associated with drug resistance. While these mutations do not compromise the ability of nevirapine to prevent mother-to-child transmission there is some concern that they may compromise future treatment options. Here we review the current data on HIV-1 drug resistance mutations and what they might mean in terms of efficacy of antiretroviral therapies to prevent mother-to-child transmission.