Importance The pandemic of coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents an unprecedented challenge to identify effective drugs for prevention and treatment. Given the rapid pace of scientific discovery and clinical data generated by the large number of people rapidly infected by SARS-CoV-2, clinicians need accurate evidence regarding effective medical treatments for this infection. Observations No proven effective therapies for this virus currently exist. The rapidly expanding knowledge regarding SARS-CoV-2 virology provides a significant number of potential drug targets. The most promising therapy is remdesivir. Remdesivir has potent in vitro activity against SARS-CoV-2, but it is not US Food and Drug Administration approved and currently is being tested in ongoing randomized trials. Oseltamivir has not been shown to have efficacy, and corticosteroids are currently not recommended. Current clinical evidence does not support stopping angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in patients with COVID-19. Conclusions and Relevance The COVID-19 pandemic represents the greatest global public health crisis of this generation and, potentially, since the pandemic influenza outbreak of 1918. The speed and volume of clinical trials launched to investigate potential therapies for COVID-19 highlight both the need and capability to produce high-quality evidence even in the middle of a pandemic. No therapies have been shown effective to date.

https://jamanetwork.com/journals/jama/articlepdf/2764727/jama_sanders_2020_rv_200005.pdf

Pharmacologic Treatments for Coronavirus Disease 2019 (COVID-19): A Review.

A novel infectious disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was detected in Wuhan, China, in December 2019. The disease (COVID-19) spread rapidly, reaching epidemic proportions in China, and has been found in 27 other countries. As of February 27, 2020, over 82,000 cases of COVID-19 were reported, with > 2800 deaths. No specific therapeutics are available, and current management includes travel restrictions, patient isolation, and supportive medical care. There are a number of pharmaceuticals already being tested [1, 2], but a better understanding of the underlying pathobiology is required. In this context, this article will briefly review the rationale for angiotensin-converting enzyme 2 (ACE2) receptor as a specific target.

/pdf/angiotensin-converting-enzyme-2-ace2-as-a-sars-cov-2-3drxdjxi93.pdf

Angiotensin-converting enzyme 2 (ACE2) as a SARS-CoV-2 receptor: molecular mechanisms and potential therapeutic target.

SARS-CoV-2 Receptor ACE2 Is an Interferon-Stimulated Gene in Human Airway Epithelial Cells and Is Detected in Specific Cell Subsets across Tissues.

The FDA-approved drug ivermectin inhibits the replication of SARS-CoV-2 in vitro.

Therapeutic options in response to the 2019-nCoV outbreak are urgently needed. Here, we discuss the potential for repurposing existing antiviral agents to treat 2019-nCoV infection (now known as COVID-19), some of which are already moving into clinical trials. Therapeutic options in response to the 2019-nCoV outbreak are urgently needed. Here, we discuss the potential for repurposing existing antiviral agents to treat 2019-nCoV infection (now known as COVID-19), some of which are already moving into clinical trials.

Therapeutic options for the 2019 novel coronavirus (2019-nCoV).

A farmer's guide to increasing soil organic carbon under pastures

Incorporation of perennial pastures into cropping rotations can improve whole-farm productivity, profitability and sustainability of mixed farming systems in southern Australia. However, success in establishing perennial pastures depends on choice of species, time of sowing, method of establishment, seasonal conditions, and whether sowing is under a cover-crop. Field experiments were sown from 2008 to 2010 to determine effects of sowing time and the presence of a cover-crop on the performance of four perennial pasture species, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), phalaris (Phalaris aquatica L.) and cocksfoot (Dactylis glomerata L.), at Yerong Creek, New South Wales (NSW). Results showed that lucerne was the most productive pasture, followed by chicory and phalaris, with cocksfoot being the poorest performer. Under favourable seasonal conditions, lucerne and chicory pastures produced 29.3 and 25.0 t ha–1 of total dry matter (DM), comprising 71% and 52%, respectively, of sown perennial species in the sward in their second growing season, when sown in autumn. Spring-sown pastures produced 24.6 and 18.3 t ha–1 of total DM in the second season, with 55% and 47% of sown species in the sward being lucerne and chicory, respectively. However, spring-sown pastures contained a very low proportion of subterranean clover (Trifolium subterraneum L.) in the sward in the first 2 years, despite efforts to broadcast seeds at the break of season in the following year. It is recommended that non-legume perennial species, such as chicory and phalaris, be sown in autumn with companion annual legumes until methods are developed and tested to establish annual legumes reliably in spring. However, lucerne can be established in autumn or spring because it can fix its own nitrogen and is not reliant on a companion legume. Cocksfoot cv. Kasbah, in general, appears less suitable than the other perennial species for this medium-rainfall environment in southern NSW. Our study showed that pastures sown without a cover-crop had the most reliable establishment, whereas pastures sown with a cover-crop in a dry year had poor establishment or total failure, as well as a significant reduction of grain yield from the cover-crop. In a wet year, pastures established satisfactorily under a cover-crop; however, growth of the cover-crop still suppressed pasture DM production in subsequent years. Research is under way to model our data to determine the likely financial implications of establishing perennial pastures under cover-crops.

https://bioone.org/journals/Crop-and-Pasture-Science/volume-65/issue-10/CP13447/Time-of-sowing-and-the-presence-of-a-cover-crop/10.1071/CP13447.pdf

Time of sowing and the presence of a cover-crop determine the productivity and persistence of perennial pastures in mixed farming systems

The effects of defoliation on plant community, root biomass and nutrient allocation and soil chemical properties on semi-arid steppes in northern China

Phalaris (Phalaris aquatica L.)-based pastures were established with and without lime in 1992 as a part of a long-term pasture–crop rotation experiment (Managing Acid Soils Through Efficient Rotations). Pre- and post-grazing pasture dry matter, phalaris basal cover and proportion of phalaris in sward were measured since 1992. In general, phalaris persisted well and its productivity was high on the highly acidic soil studied in the current experiment, and this was improved on the limed treatment. After establishment in 1992, the average proportion of phalaris in spring 2001 was 32.1% in the limed treatment and 15.6% in the unlimed treatment. Basal cover at the end of summer 2002 was 4.5% and 2.0% for the limed and unlimed treatments, respectively. The results from the current experiment showed that subsurface acidity (low pHCa and high exchangeable aluminium percentage in the 10–30 cm soil depth) had significant impacts on phalaris persistence. It is concluded that subsurface pH was one of the major constraints for the persistence of phalaris. The long-term management of soil acidity should aim to eliminate the exchangeable aluminium from the soil profile by maintaining a high pHCa (5.5 or above) in the 0–10 cm soil depth. Rainfall during growing season had no direct effect on phalaris persistence. Nevertheless, feed scarcity in dry years due to moisture stress often exacerbated grazing pressure on phalaris, which may affect the phalaris persistence indirectly. It is the grazing management in autumn and summer that had significant effects on phalaris persistence. It is suggested that rotational grazing plus strategic rest if possible in autumn could prolong the life of phalaris-based pastures. Repeated heavy grazing should be avoided during summer, particularly after light to moderate summer rainfall events have stimulated sprouting.

/pdf/phalaris-persistence-under-rotational-grazing-on-a-highly-4hnqkqnh8s.pdf

Guangdi Li

Papers

A farmer's guide to increasing soil organic carbon under pastures

Time of sowing and the presence of a cover-crop determine the productivity and persistence of perennial pastures in mixed farming systems

The effects of defoliation on plant community, root biomass and nutrient allocation and soil chemical properties on semi-arid steppes in northern China

Phalaris persistence under rotational grazing on a highly acidic soil on the south-west slopes of New South Wales

Antifungal activity of spider venom-derived peptide lycosin-I against Candida tropicalis.