Organisms at the edge of life

Viruses are by far the most abundant biological entities on Earth and they outnumber all the others put together. But are they a form of life or an organic structure?

Viruses contain genetic material, reproduce and evolve. However, they do not posses a true cellular structure, which is often regarded as the basic unit of life, or have their own metabolism. For this reason they are referred to as “organisms at the edge of life” and opinion is still divided on whether they are a life form, or organic structures that interact with living organisms.

Viruses are tiny, about 100 times smaller than bacterial cells. Although their pathogenic qualities were known they eluded discovery as the causative agent until relatively recently in our scientific history. Most viruses cannot be seen with an optical microscope and their structure was not described until the invention of electron microscopy in 1931.

Outside a host organism viruses exist as particles called virions. They consist of genetic material, DNA or RNA, surrounded by a protective protein coat. Some viruses also have a lipid envelope.

A virus relies on a host to replicate, they require the metabolism of the host cell to assemble copies of themselves. They infect all types of cellular life including animals, plants, bacteria and fungi. Some can only infect a limited range of hosts and can be species specific while others have a broad range. For example, smallpox can only infect humans while the rabies virus can infect a variety of mammals.

Transmission of viruses can be vertical, from mother to offspring, or horizontal, from host to host. Horizontal transmission can occur via a number of pathways; transmission of body fluids such as blood or saliva, spread by coughing and sneezing, entering the body in food or water by the faecal–oral route and a range of vectors such as mosquitoes, or aphids that transfer sap from plant to plant.

Most viruses elicit an immune response in host organisms, eliminating the virus and providing immunity to future infections. Some viruses elude this immune response by constantly changing the structure of their surface proteins. Viruses are difficult to treat because they use the hosts’ metabolic pathways to reproduce, drugs that interfere with viral replication can also cause toxic effects to the host. Vaccination has proven to be the most effective medical intervention, providing immunity to infection.

However, most viruses are fragile when outside a host organism. The simple act of washing your hands with soap is one of the most effective ways of preventing infection and spread. By surrounding the viruses on your skin with soap, a surfactant, the lipid envelopes enclosing the virus are ruptured, spilling essential proteins and rendering the virus useless.

Building capacity in rural women

In rural communities, many women have limited training opportunities. But Mudgee’s Women in Ag group aims to ameliorate that by allowing participating Watershed Landcare members to explore topics of interest and build capacity through mentoring, peer support, sharing of knowledge and skills and expert speakers.

In recognition of the shortage of professional development available to women working in agriculture or ag related industries, Watershed Landcare received funding from the Central West LLS to run a personal development program for rural women in 2015.

The program delivered targeted training, mentoring and built support networks to strengthen resilience, provide leadership opportunities and access to training and support services that enhanced confidence and skills through delivery of training workshops, webinars, and a regional forum.

“The feedback from the program was overwhelmingly positive. The women involved learned a lot and had so much fun we decided to keep it going.” said Agness Knapik, Watershed Landcare Coordinator.

“The aim of the Women in Agriculture group is to champion rural women by providing support, mentoring and professional development through vibrant and interactive conversation, and exposure to new ideas, approaches and innovation.” she continued.

The group is now in it’s fifth year and in that time has covered diverse topics such as social media, leadership and team dynamics, handling stress and building resilience, personal goal setting, conflict resolution, accounting, book keeping and financial training, fermentation, gardening and has conducted a number of field trips to visit local farms and businesses.

The women involved have diverse backgrounds, from grazing and horticulture to running their own food manufacturing plants and natural resource management.

The Women in Ag group meets once a month for a cuppa and a chat and to explore a topic of interest and provides an opportunity to ask questions and share experiences and skills. Specialist speakers are also engaged to run workshops on different topics.

The Women in Ag group meets on the last Thursday of the month from 9:30-11:30am. Last month the group visited a local garden to learn about the design principles utilised when the garden was established and the strategies utilised to survive the recent drought.

Want to get involved? Contact Watershed Landcare Co-ordinator, Agness Knapik, on 0435 055 493 or email: info@watershedlandcare.com.au.

The Women in Ag group is supported by Watershed Landcare and is a part of the NSW Landcare Program, supported through the partnership of Local Land Services and Landcare NSW.

Knowledge and Skill: Last month the Women in Ag group visited a local garden to learn about design principles and drought strategies.

So why is soil pH important?

If you have ever had a soil test done you will have noticed one of the first parameters to be listed in the results is pH. But what is soil pH and why is it important?

Soil pH represents the degree of acidity or alkalinity and is a measure of the concentration of hydrogen ions in the soil solution. Soil pH ranges between about 3 (very acidic) to 10 (very alkaline). In our region soils typically have a pH range of 4.5-7, but can be as high as 8 or 9 in areas with limestone outcrops.

The pH of a substrate, like soil, affects the behaviour of the chemicals contained within it; influencing the form of these substances and the reactions and chemical processes they undergo. The acidity of soil impacts on the availability of elements and compounds, both beneficial and detrimental, to plants.

Compounds from the soil enter plants via their root system and must be present in a soluble form in order to be taken up with water. Different plant species are adapted to soils of different pH ranges and some have adapted to cope with extremes, but in general the optimum is between pH 5.5 and 8. In this range essential nutrients needed for plant growth are available in abundance in their soluble form and harmful substances are not present at toxic levels.

Deficiencies in essential nutrients are a limiting factor for plant metabolism and result in slow growth rates and poor yields. For example, zinc, which is required in a large number of plant enzymes and plays a crucial role in DNA transcription, and copper, which is necessary for photosynthesis, are present in their soluble forms at soil pH 4.5-8. Soil pH between 5.5 and 8 provides the most favourable conditions for maintaining essential macro and micro-nutrients in their plant-available forms.

Conversely, aluminium is insoluble in this range. This is good news because aluminium, which is present in all soils, is extremely toxic to plants in its soluble form. Aluminium severely limits root growth by inhibiting a number of physiological pathways, and plants experiencing toxicity can exhibit moisture stress even when the soil is relatively moist.

Whether it’s in your garden, crop or pasture, if you are examining the factors that are constraining plant growth, checking the pH of your soil might be a good place to start.