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Although South Africa is known as one of the most biodiverse countries in the world, based on its unique plants and animals, microorganisms have received much less attention. Microorganisms in general and actinobacteria in particular are an underexplored source of new medicines. Recent studies have demonstrated the presence of diverse cultivable actinobacteria from various biomes. However, investigations of the natural product diversity associated with these microorganisms are lacking. We hereby present a review of natural products isolated from South African actinobacteria together with their biological activities. Many of these natural products are structurally novel and include compounds belonging to the following classes: anthraquinones, isoflavonoids, ketolides, macrolides, macrolactams, tripeptides and depsipeptides. They show a wide range of biological activities including antibacterial, antifungal, cytotoxic and antitumour activities.

Many aspects of birdsong vary seasonally, but we know almost nothing about seasonal variation in vocal mimicry, a conspicuous feature of the songs of 15–20% of bird species. I sampled spontaneous song from nine, free‐living, male northern mockingbirds Mimus polyglottos four times during the calendar year – three times during the breeding season, and once during the non‐breeding season. Results showed that mockingbirds did not mimic summer migrants significantly more during any sampling period. Results also showed significant differences across sampling periods in the frequency, but not diversity, of mimicry. Frequency of mimicry was highest in late spring (61.3%) and lowest during the non‐breeding season (48.3%), suggesting mimicry might play a role in reproductive stimulation of multiple‐brooded females. Because mockingbirds mimicked summer migrants throughout the year, regardless of whether migrants were present, mimicry is unlikely to facilitate interspecies communication. Seasonal patterns also suggest that females might be attracted to a high frequency of mimicry, but not to a high diversity of mimicry. I argue that observational studies of seasonal variation in additional mimics could provide key insights into the functional role of vocal mimicry.

In this paper, we report on the chemistry of the rare South African Actinomycete Kribbella speibonae strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine 1 and desoxy-desferrioxamine D1 2, have been isolated, together with four known hydroxamates, desferrioxamine D1 3, desferrioxamine B 4, desoxy-nocardamine 5 and nocardamine 6, and a diketopiperazine (DKP) 7. The structures of 1–7 were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature. Three new dehydroxy desferrioxamine derivatives 8–10 were tentatively identified in the molecular network of K. speibonae strain SK5 extracts, and structures were proposed based on their MS/MS fragmentation patterns. A plausible spb biosynthetic pathway was proposed. To the best of our knowledge, this is the first report of the isolation of desferrioxamines from the actinobacterial genus Kribbella.

Objectives: To assess whether preoperative levels of physical activity predict the incidence of post-operative complications following anatomical lung resection. Methods: Levels of physical activity (daily steps) were measured for 15 consecutive days using pedometers in 90 consecutive patients (prior to admission). Outcomes measured were cardiac and respiratory complications, length of stay, and 30-day re-admission rate. Results: A total of 78 patients’ datasets were analysed (12 patients were excluded due to non-compliance). Based on steps performed they were divided into quartiles; 1 (low physical activity) to 4 (high physical activity). There were no significant differences in age, smoking history, COPD, BMI, percentage predicted FEV1 and KCO and cardiovascular risk factors between the groups. There were significantly fewer total complications in quartiles 3 and 4 (high physical activity) compared to quartiles 1 and 2 (low physical activity) (8 vs 22; P = .01). There was a trend (P > .05) towards shorter hospital length of stay in quartiles 3 and 4 (median values of 4 and 5 days, respectively) compared to quartiles 1 and 2 (6 days for both groups). Conclusions: Preoperative physical activity can help to predict postoperative outcome and can be used to stratify risk of postoperative complications and to monitor impact of preoperative interventions, ultimately improving short term outcomes.

Many animal species imitate the sounds of other species, but we know little about why vocal mimics copy some species while failing to copy other species, i.e., 'model selection'. In this observational study of free-living northern mockingbirds (Mimus polyglottos), I tested five hypotheses of model selection: (1) Proximity hypothesis: preferential imitation of species found in close proximity to the vocal mimic, (2) Aggression hypothesis: preferential imitation of species with which the mimic interacts aggressively, (3) Passive sampling hypothesis: preferential imitation of species heard frequently by the mimic, (4) Acoustic similarity hypothesis: preferential imitation of species whose sounds are acoustically similar to the non-imitative songs of the vocal mimic and (5) Alarm hypothesis: preferential imitation of alarm-associated vocalisations. The data supported only the acoustic similarity hypothesis. Given that this hypothesis has been supported in two additional mimicking lineages, it suggests a potential non-adaptive explanation for the evolution of vocal mimicry. Species that learn vocalisations are already predisposed toward learning sounds with key acoustic characteristics. Whenever natural selection favours a widening of the auditory template that guides model selection, vocal imitation of heterospecifics becomes more likely because of 'learning mistakes'.

Summary The Zephyr (PulmonX Inc., Redwood, CA) endobronchial valve (EBV), predominantly designed for lung volume reduction in emphysema, can also be used to close a spontaneous or post-operative prolonged air leak (PAL). We describe a previously unreported complication of cutaneous migration of an EBV, inserted for management of a PAL from a postoperative bronchopleural fistula (BPF), in a 62-year-old male following a right upper lobe posterior-apical (S1,2) segmentectomy. His PAL resulted in a chronic empyema which failed to respond to surgical debridement, anterior cavernostomy and pectoral myoplasty. Bronchoscopic closure of the air leak by EBV insertion resulted in clinical improvement but there was a residual chronic wound sinus through which the patient reported protrusion of a foreign body that was causing irritation. It was the EBV. We hypothesise that the BPF healed beneath the EBV causing it to dislodge but its route to the skin remains a mystery.

Tuberculosis (TB) remains a public health crisis, requiring the urgent identification of new anti-mycobacterial drugs. We screened several organic and aqueous marine invertebrate extracts for their in vitro inhibitory activity against the causative organism, Mycobacterium tuberculosis. Here, we report the results obtained for 54 marine invertebrate extracts. The chemical components of two of the extracts were dereplicated, using 1H NMR and HR-LCMS with GNPS molecular networking, and these extracts were further subjected to an activity-guided isolation process to purify the bioactive components. Hyrtios reticulatus yielded heteronemin 1 and Jaspis splendens was found to produce the bengamide class of compounds, of which bengamides P 2 and Q 3 were isolated, while a new derivative, bengamide S 5, was putatively identified and its structure predicted, based on the similarity of its MS/MS fragmentation pattern to those of other bengamides. The isolated bioactive metabolites and semi-pure fractions exhibited M. tuberculosis growth inhibitory activity, in the range <0.24 to 62.50 µg/mL. This study establishes the bengamides as potent antitubercular compounds, with the first report of whole-cell antitubercular activity of bengamides P 2 and Q 3.

Surgery remains the gold standard for patients with resectable nonsmall cell lung cancer. Current guidance identifies patients with poor pulmonary reserve to fall within a high-risk cohort. The aim of this study was to determine the clinical and quality of life outcomes of anatomical lung resection in patients deemed high risk based on pulmonary function measurements. A retrospective review of patients undergoing anatomical lung resection for nonsmall cell lung cancer between January 2013 and January 2015 was performed. All patients with limited pulmonary reserve defined as predicted postoperative forced expiratory volume in 1 s or transfer factor of the lung for carbon monoxide of <40% were included in the study. Postoperative complications, admission to the Intensive Care Unit, length of stay, and 30-day in-hospital mortality were recorded. The European Organization for Research and Treatment of Cancer quality of life questionnaire lung cancer 13 questionnaire was used to assess quality of life outcomes. Fifty-three patients met the inclusion criteria. There was no in-hospital mortality, and 30-day mortality was 1.8%. No complications were seen in 64% ( = 34), minor complications occurred in 26% ( = 14), while 9% had a major complication ( = 5). Quality of life outcomes were above the reference results for patients with early stage lung cancer. Anatomical lung resection can be performed safely in selected high-risk patients based on pulmonary function without significant increase in morbidity or mortality and with acceptable quality of life outcomes. Given that complications following lung resection are multifactorial, fitness for surgery should be thoroughly assessed in all patients with resectable disease within a multidisciplinary setting. High operative risk by pulmonary function tests alone should not preclude surgical resection.

In Paulshoek, Namaqualand, three research projects focusing on medicinal plants were developed concurrently. The projects were based in the disciplines of anthropology, botany and chemistry. In this paper, we explore how these projects related to one another and describe the conversations that occurred in the process of searching for transdisciplinary knowledge. The projects ostensibly shared a common object of knowledge, but it was through working together that the medicinal plants constituted us as a community of scholars. As our insight into our respective disciplinary relationships with the plants grew, so did our understanding of the limitations of our respective disciplinary positions. The process made possible a 'reimagination' of both the object of study and our relationships to it and to one another. The research project, conceptualised in 2009, engaged current debates on indigenous knowledge and its historical erasures, and offered an approach that has potential to produce new knowledges while respecting the integrity of the disciplines. This approach requires a non-competitive attitude to research and one that acknowledges the contributions that can be made by multiple approaches.