Notes on the Forests of Southern Iowa

In the southernmost tier of counties in Iowa, particularly in Jefferson, Van Buren, Wapello, Davis, Monroe, Appanoose, Lucas and Wayne counties there exist rather extensive natural forests of oak and other hardwood species. These counties lie within an area of considerable loessal soils. This part of the state has been designated in agricultural parlance as the southern Iowa pasture section. The relief of the land in these parts consists of a rather distinct upland plain lying generally about 1000 feet above sea-level. Dissection of this plain by drainage has resulted in numerous fingering and tortuous headwaters creating slopes or terraces, and flat to narrow ridges and bottoms of variable widths and patterns. The plain is composed of a number of soil types in; the Clinton silt loam, the Lindley silt loam, the Edina, the Marion and Grundy silt loams, etc. The Clinton silt loam is one of the most prevalent upland loess soils; it has a light gray yellow and buff color and a loose texture. It over-lies much of the loose and erosive Lindley drift soil which comprises a goodly proportion of the slope land. Some upland sections contain small quantities of the whitish Edina and powdery Marion soils. In the bottoms we find generally deep accumulations of the dark and fertile Wabash silt loam

Professional Concerns

In the contribution which follows, Collett B. Dilworth, Jr., of the English Department at East Carolina University, gets to the very heart of why literature is taught in schools. He broaches the question of how literary study relates to the basic skills, and he ties his rationale in with questions of accountability and its handmaiden, competency testing. Probably the heart of Dilworth\u27s argument is in his statement, The student of literature is not primarily looking for information, s/he is looking for experience

Ex Vivo Modeling of Chemical Synergy in Prenatal Kidney Cystogenesis

Cyclic adenosine monophosphate (cAMP) drives genetic polycystic kidney disease (PKD) cystogenesis. Yet within certain PKD families, striking differences in disease severity exist between affected individuals, and genomic and/or environmental modifying factors have been evoked to explain these observations. We hypothesized that PKD cystogenesis is accentuated by an aberrant fetal milieu, specifically by glucocorticoids. The extent and nature of cystogenesis was assessed in explanted wild-type mouse embryonic metanephroi, using 8-Br-cAMP as a chemical to mimic genetic PKD and the glucocorticoid dexamethasone as the environmental modulator. Cysts and glomeruli were quantified by an observer blinded to culture conditions, and tubules were phenotyped using specific markers. Dexamethasone or 8-Br-cAMP applied on their own produced cysts predominantly arising in proximal tubules and descending limbs of loops of Henle. When applied together, however, dexamethasone over a wide concentration range synergized with 8-Br-cAMP to generate a more severe, glomerulocystic, phenotype; we note that prominent glomerular cysts have been reported in autosomal dominant PKD fetal kidneys. Our data support the idea that an adverse antenatal environment exacerbates renal cystogenesis

Mechanisms underpinning adaptations in placental calcium transport in normal mice and those with fetal growth restriction

Fetal delivery of calcium, via the placenta, is crucial for appropriate skeletal mineralization. We have previously demonstrated that maternofetal calcium transport, per gram placenta, is increased in the placental specific insulin-like growth factor 2 knockout mouse (P0) model of fetal growth restriction (FGR) compared to wild type littermates (WTL). This effect was mirrored in wild-type (WT) mice comparing lightest vs. heaviest (LvH) placentas in a litter. In both models increased placental calcium transport was associated with normalization of fetal calcium content. Despite this adaptation being observed in small normal (WT), and small dysfunctional (P0) placentas, mechanisms underpinning these changes remain unknown. Parathyroid hormone-related protein (PTHrP), elevated in cord blood in FGR and known to stimulate plasma membrane calcium ATPase, might be important. We hypothesized that PTHrP expression would be increased in LvH WT placentas, and in P0 vs. WTL. We used calcium pathway-focused PCR arrays to assess whether mechanisms underpinning these adaptations in LvH WT placentas, and in P0 vs. WTL, were similar. PTHrP protein expression was not different between LvH WT placentas at E18.5 but trended toward increased expression (139%; P = 0.06) in P0 vs. WTL. PCR arrays demonstrated that four genes were differentially expressed in LvH WT placentas including increased expression of the calcium-binding protein calmodulin 1 (1.6-fold; P < 0.05). Twenty-four genes were differentially expressed in placentas of P0 vs. WTL; significant reductions were observed in expression of S100 calcium binding protein G (2-fold; P < 0.01), parathyroid hormone 1 receptor (1.7-fold; P < 0.01) and PTHrP (2-fold; P < 0.05), whilst serum/glucocorticoid-regulated kinase 1 (SGK1), a regulator of nutrient transporters, was increased (1.4 fold; P < 0.05). Tartrate resistant acid phosphatase 5 (TRAP5 encoded by Acp5) was reduced in placentas of both LvH WT and P0 vs. WTL (1.6- and 1.7-fold, respectively; P < 0.05). Signaling events underpinning adaptations in calcium transport are distinct between LvH placentas of WT mice and those in P0 vs. WTL. Calcium binding proteins appear important in functional adaptations in the former whilst PTHrP and SGK1 are also implicated in the latter. These data facilitate understanding of mechanisms underpinning placental calcium transport adaptation in normal and growth restricted fetuses

Determination of Soil Moisture Content at Permanent Wilting for Us in Field Studies

In ecological investigations of interactions between plants and soil moisture, whether the aim is to determine fundamental plant-environment relationships or primarily to solve immediate plant production problems, the soil moisture content at permanent wilting, expressed as a percentage of the dry weight, is a basic determination. Although there is evidence that this soil moisture value may not represent the exact non-available moisture content of the soil (4, 8) it is generally agreed that it represents the limit of favorable plant growth conditions and will be considered here as non-available soil moisture

Selection of Australian Root Nodule Bacteria for Broad-Scale Inoculation of Native Legumes

The unique and diverse native Australian perennial legumes are under current investigation for use as pastures in Australian agriculture. Identification of root nodule bacteria (RNB) that can fix nitrogen effectively for the plant is a critical factor for the success of a legume species in agriculture (Howieson et al., 2000). Some legumes under investigation are relatively promiscuous (Lange, 1961). This trait may allow the development of a single, broad-scale inoculant that could allow inoculation of multiple species of agricultural importance, whilst more effective, specific RNB are developed in time. Aimed to identify strains that can form effective symbioses with several native legume species of potential interest to agriculture, this experiment screened putative indigenous RNB on 5 native legumes