Type IV Secretion-Dependent Activation of Host MAP Kinases Induces an Increased Proinflammatory Cytokine Response to Legionella pneumophila

The immune system must discriminate between pathogenic and nonpathogenic microbes in order to initiate an appropriate response. Toll-like receptors (TLRs) detect microbial components common to both pathogenic and nonpathogenic bacteria, whereas Nod-like receptors (NLRs) sense microbial components introduced into the host cytosol by the specialized secretion systems or pore-forming toxins of bacterial pathogens. The host signaling pathways that respond to bacterial secretion systems remain poorly understood. Infection with the pathogen Legionella pneumophila, which utilizes a type IV secretion system (T4SS), induced an increased proinflammatory cytokine response compared to avirulent bacteria in which the T4SS was inactivated. This enhanced response involved NF-κB activation by TLR signaling as well as Nod1 and Nod2 detection of type IV secretion. Furthermore, a TLR- and RIP2-independent pathway leading to p38 and SAPK/JNK MAPK activation was found to play an equally important role in the host response to virulent L. pneumophila. Activation of this MAPK pathway was T4SS-dependent and coordinated with TLR signaling to mount a robust proinflammatory cytokine response to virulent L. pneumophila. These findings define a previously uncharacterized host response to bacterial type IV secretion that activates MAPK signaling and demonstrate that coincident detection of multiple bacterial components enables immune discrimination between virulent and avirulent bacteria

G80-526 The Effect of Weather on Corn: Preseason Precipitation and Yield of Unirrigationed Corn

This NebGuide examines the results of studies done on the effects of weather on unirrigationd corn. Studies of the effects of weather on unirrigationd corn in Nebraska between 1950 and 1974 show the following four factors to be closely related to yield: Technology--the availability of better hybrids, nitrogen fertilizer, herbicides, insecticides and other improvements have resulted in a yield increase averaging 1.3 bushel per acre per year since 1950. Preseason precipitation--that which occurred between September 1 and May 15 had a beneficial effect. Yield increased on the average of 1.1 bushel per acre for each inch that preseason precipitation was above normal. Temperature stress--this had a negative effect during ear formation, tasseling and grain filling stages. Yield decreased an average of 1 bushel per acre for every day between ear formation (12-leaf stage) and denting that temperature was 95°F or higher. Rainfall during grain fill--this had a positive effect. Yield increased an average of 1.5 bushel per acre for each inch of rainfall between tasseling and denting

G81-552 Effects of Weather on Corn Planting and Seedling Establishment

Corn planting usually begins when the average daily temperature first rises 55°F and the soil becomes sufficiently warm enough to initiate germination and sustain seedling growth. This may be as early as the middle of March in central Texas 700 miles south of Nebraska or as late as the middle of May in central South Dakota. Corn may be planted as early as the first week of April in southeast Nebraska and continue into the first week of June. Most of the corn, however, is planted between May 4 and May 21. Corn planted early when the temperature is cool takes longer to germinate and become established than at later planting dates. Reserves in the seed surrounding the germinating embryo provide food to nourish the young seedling for about 21 days. After this, the roots must be sufficiently well established to extract nutrients from the soil and two leaves must be developed to begin the important function of photosynthesis. The young plant is not well established until this occurs

G86-796 Growing Degree Day Requirements and Freeze Risk as a Guide to Selecting and Planting Corn Hybrids

This NebGuide discusses the growing degree day requirements for Nebraska\u27s four corn-growing regions, and how using these requirements can aid in planting date decisions. Variations between locations, between seasons at a particular location, between planting times at a particular location and season, and between the requirements of different hybrids result in differences in the number of days it takes for corn to mature. These variations in days are all closely related to differences in temperatures when the corn is being grown

Growing Season Air-Soil Temperature Relationships at Lincoln, Nebraska

This study concerns the use of weekly average air temperature for predicting weekly average soil temperature under different conditions of surface cover during different times of year. Probabilities of weekly average air temperature for Lincoln as well as other Nebraska locations are available. These probabilities and the soil temperature prediction equations may be used in determining expected soil temperatures

G83-673 Maturity Dates and Freeze Risks Based on Growing Degree Days

Explanation of growing degree days (GDD) necessary for crop maturity and tables showing estimated maturity dates and freeze risks for different GDD accumulations for different planting times in regions of Nebraska. The concept of growing degree days (GDD) resulted from observations that: There is a base temperature below which plants do not grow. The rate of growth increases with temperature above this base. Crop hybrids require different GDD accumulations to reach maturity

EC81-1240 Vegetable Gardening in Nebraska

Nebraskans are increasing their consumption of fresh vegetables — as appetizers, salads, side dishes, and snacks. Fresh vegetables are an integral part of a healthy, well-balanced diet. Although Nebraska\u27s climate and soil are well-suited for many vegetables, most are supplied from out of the state, even during summer. Growing fresh vegetables can provide higher nutrition and flavor at less expense than buying fresh produce at the grocery store. A garden also can be a source of personal enjoyment and satisfaction. This extension circular helps the gardener decide when, where, and how to plant and maintain a vegetable garden

EC86-1244 Vegetable Producction in Nebraska

Vegetable research at the University of Nebraska concerns studies of the culture, processing, mechanization of production and marketing of vegetable crops with the objective of increasing production, quality and use of crops and products process from them. This circular presents a portion of results from investigations into the production, marketing and processing of vegetables in Nebraska. Information concerning climate, soil and water resources is presented and discussed. Also summarized are results from vegetable yield trials conducted at different locations in the state during the seven-year period 1960-66