Responses of soil-grown Scots pine seedlings to experimental warming, moderate nitrogen addition and bark herbivory in a three-year field experiment.

Increased soil nitrogen (N), warming and bark herbivory all are expected to affect boreal forests in the future. We studied the effects of warming (0.5 °C and 4.0 °C above ambient air and soil temperature, respectively), moderate N addition (30 kg N ha-1 y-1) and bark herbivory by large pine weevil (Hylobius abietis L.) on soil-grown Scots pine (Pinus sylvestris L.) seedlings in a three-year (2014-2016) open-air field experiment. Seedling dry mass, root mass fraction (RMF), root morphology, mycorrhizal colonization, mycorrhizal morphotypes, root phenolics and microbial abundance in the rhizosphere area were studied. We observed that both moderate N addition and warming showed interactive effects, and generally improved seedling growth after the three consecutive growing seasons. However, soil dryness was increased due to combined warming and N addition treatment in 2016, and it seemed to limit the shoot growth stimulation as well as increase the dependence of the non-herbivory seedlings on the mycorrhizas. Moderate N addition generally reduced herbivory damage intensity and increased RMF. It also decreased total mycorrhizal colonization rate and increased SRL of the seedlings in 2016, but only in the absence of other factors. In 2016, herbivory affected soil exploration efficiency and mycorrhizal colonization without other factors, and had a tendency to increase root phenolics. There were only minor effects of N addition and herbivory on soil microbial abundances. We conclude that warming and N addition to soil may increase growth in young Scots pine if soil drought or herbivory do not start to limit it; and that in young Scots pine stands moderate bark herbivory are likely to affect roots more than shoots.

Effect of medicinal plants on Moraxella cattarhalis.

OBJECTIVE: To determine the antimoraxella activity of Ethiopian medicinal plants extracts. METHODS: Two clinical isolates of Moraxella cattarhalis (M. cattarhalis) with different antibiotic sensitivity pattern were tested to determine their susceptibility to garlic [Allium sativum (A. sativum)], bark of cinnamon [Cinnamomum zeylanicum (C. zeylanicum)], clove [Syzygium aromaticum (S. aromaticum)], and leaves of avocado [Persea americana (P. americana)], rosemary [Rosmarinus officinalis (R. officinalis)] and prickly poppy [Argemone mexicana (A. mexicana)]. Disk diffusion assay and broth dilution method were used to measure zone of inhibition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant extracts against M. cattarhalis. RESULTS: Both the strains of M. cattarhalis exhibited similar sensitivities to the extracts of medicinal plants. Antimoraxella activity was exhibited only by garlic, avocado leaves and cinnamon. Garlic was found to be more antagonistic to M. cattarhalis than cinnamon and avocado. Garlic and avocado leaves have shown similar MIC (30 mg/mL) where as their zone of inhibition (15 and 11 mm, respectively) were different. CONCLUSIONS: Garlic, cinnamon and avocado leaves extracts represents alternative source of natural antimicrobial substances for use in clinical practice for the treatment of cases of M. cattarhalis. Further research on the effects of these extracts on M. cattarhalis can be rewarding to pursue in the search for new broad spectrum antimicrobial agents.

An overnight sedimentation method: improving the diagnosis of tuberculosis when electrical centrifuge is not available.

An experimental comparative study was conducted in order to compare the positivity pattern of sputum microscopy using the direct and overnight sedimentation Ziehl-Neelsen (ZN) smears, direct and NaOCl pretreated centrifuged ZN smears and overnight sedimentation and NaOC1 pretreated centrifuged ZN smears methods. We examined 660 sputum smeared slides for the presence of acid-fast bacillus from 220 sputum samples. Compared with the direct microscopy method, positivity increased by 91.1% after centrifugation (P < 0.001, chi(2) = 18.27) and by 71.1% after overnight sedimentation (P < 0.001, chi(2) = 11.61). No statistical significant difference was observed between the results of two different concentration techniques (P > 0.05, chi(2) = 0.789). The application of overnight sedimentation (in a laboratory without electricity) and/or the centrifugation technique could make a positive impact on the effectiveness of national tuberculosis control programmes.

Nocardiosis in HIV seropositive clinically suspected pulmonary tuberculosis patients.

To determine the frequency of nocardiosis in HIV-positive individuals clinically suspected of having tuberculosis (TB), 140 sputum samples were collected and processed by Gram stain, modified Ziehl-Neelsen staining and by culture on Lowenstein Jensen medium. Four (2.85%) patients were positive for nocardia by microscopy and five (3.6%) had positive culture for Nocardia asterioides. In areas where HIV-associated TB is common, some patients diagnosed as smear-negative pulmonary TB will actually have nocardiosis. Clinicians should be aware of this entity in HIV/immunocompromised patients with respiratory infections who fail to respond to antituberculous treatment.