Early environment influences later performance in fishes

Conditions fish encounter during embryogenesis and early life history can leave lasting effects not only on morphology, but also on growth rate, life‐history and behavioural traits. The ecology of offspring can be affected by conditions experienced by their parents and mother in particular. This review summarizes such early impacts and their ecological influences for a variety of teleost species, but with special reference to salmonids. Growth and adult body size, sex ratio, egg size, lifespan and tendency to migrate can all be affected by early influences. Mechanisms behind such phenotypically plastic impacts are not well known, but epigenetic change appears to be one central mechanism. The thermal regime during development and incubation is particularly important, but also early food consumption and intraspecific density can all be responsible for later life‐history variation. For behavioural traits, early experiences with effects on brain, sensory development and cognition appear essential. This may also influence boldness and other social behaviours such as mate choice. At the end of the review, several issues and questions for future studies are given.     

Nutrients are assimilated efficiently by Lymantria dispar caterpillars from the mature leaves of trees in the Salicaceae

The efficient aquisition of nutrients from leaves by insect herbivores increases their nutrient assimilation rates and overall fitness. Caterpillars of the gypsy moth (Lymantria dispar L.) have high protein assimilation efficiencies (PAE) from the immature leaves of trees such as red oak (Quercus rubra) and sugar maple (Acer saccharum) (71–81%) but significantly lower PAE from their mature leaves (45–52%). By contrast to this pattern, both PAE and carbohydrate assimilation efficiencies (CAE) remain high for L. dispar larvae on the mature leaves of poplar (Populus alba × Populus tremula) grown in greenhouse conditions. The present study tests two alternative hypotheses: (i) outdoor environmental stresses cause decreased nutrient assimilation efficiencies from mature poplar leaves and (ii) nutrients in the mature leaves of trees in the poplar family (Salicaceae) remain readily available for L. dispar larvae. When poplar trees are grown in ambient outdoor conditions, PAE and CAE remain high (approximately 75% and 78%, respectively) in L. dispar larvae, in contrast to the first hypothesis. When larvae feed on the mature leaves of species in the Salicaceae [aspen (Populus tremuloides), cottonwood (Populus deltoides), willow (Salix nigra) and poplar], PAE and CAE also remain high (68–76% and 72–92%, respectively), consistent with the second hypothesis. Larval growth rates are strongly associated with protein assimilation rates, and more strongly associated with protein assimilation rates than with carbohydrate assimilation rates. It is concluded that tree species in the Salicaceae are relatively high‐quality host plants for L. dispar larvae, in part, because nutrients in their mature leaves remain readily available.     

Cloning and restriction fragment length polymorphism analysis of a cDNA for swine PIT-1, a gene controlling growth hormone expression*

A partial swine cDNA which encodes the functional domain of PIT-1 was isolated by the polymerse chain reaction (PCR). The swine PIT-1 cDNA clone is 95% identical at the protein level to the rat Pit-1 gene. Thus, Pit-l's known function in control of rat growth hormone and prolactin expression is likely to be conserved in swine. This swine cDNA clone was used to investigate genetic variability at PIT-1 in several American and Chinese breeds. Polymorphic BamIII fragments were found in pure-bred Meishan animals (n= 13), but only monomorphic fragments in five American breeds (n= 36).     

Osmotic relations during elongation growth in hypocotyls of Helianthus annum L.

The relationship between growth, change in cell osmotic pressure and accumulation of osmotic solutes was investigated in hypocotyls of sunflower (Helianthus annum L.) seedlings. During growth in darkness the osmotic pressure decreased by 50% between days 2 and 6 after sowing. After irradiation of dark-grown seedlings with continuous white light (WL) an inhibition of hypocotyl growth was measured, but the osmotic pressure of the growing cells was not lower than in the dark-grown control. Growth in darkness and after WL irradiation was accompanied by an increase in the amount of osmotic substances (soluble sugars) which was proportional to the increase in length of the organ. During growth in continuous WL the cell osmotic pressure decreased by 45 % between days 2 and 6 after sowing. The transfer of WL-grown seedlings to darkness (“re-etiolation”) resulted in a rapid acceleration of hypocotyl growth, but the cell osmotic pressure was the same as that of the WL grown control. Growth in continuous WL was accompanied by a corresponding accumulation of osmotic substances (soluble sugars). The transition from WL to darkness resulted in an enhanced accumulation of osmotica and an increase in cell-wall extensibility. The results indicate that the relative maintenance of cell osmotic pressure during rapid hypocotyl growth in darkness is caused by an enhanced accumulation of soluble sugars into the growing cells of the organ.     

Collagen and non-collagenous proteins molecular crosstalk in the pathophysiology of osteoporosis

Collagenous and non-collagenous proteins (NCPs) in the extracellular matrix, as well as the coupling mechanisms between osteoclasts and osteoblasts, work together to ensure normal bone metabolism. Each protein plays one or more critical roles in bone metabolism, sometimes even contradictory, thus affecting the final mechanical, physical and chemical properties of bone tissue. Anomalies in the amount and structure of one or more of these proteins can cause abnormalities in bone formation and resorption, which consequently leads to malformations and defects, such as osteoporosis (OP). The connections between key proteins involved in matrix formation and resorption are far from being elucidated. In this review, we resume knowledge on the crosstalk between collagen type I and selected NCPs (Transforming Growth Factor-β, Insulin-like Growth Factor-1, Decorin, Osteonectin, Osteopontin, Bone Sialoprotein and Osteocalcin) of bone matrix, focusing on their possible involvement and role in OP. The different elements of this network can be pharmacologically targeted or used for the design/development of innovative regenerative strategies to modulate a feedback loop in bone remodelling.     

SOCS2 Balances Metabolic and Restorative Requirements during Liver Regeneration

After significant injury, the liver must maintain homeostasis during the regenerative process. We hypothesized the existence of mechanisms to limit hepatocyte proliferation after injury to maintain metabolic and synthetic function. A screen for candidates revealed suppressor of cytokine signaling 2 (SOCS2), an inhibitor of growth hormone (GH) signaling, was strongly induced after partial hepatectomy. Using genetic deletion and administration of various factors we investigated the role of SOCS2 during liver regeneration. SOCS2 preserves liver function by restraining the first round of hepatocyte proliferation after partial hepatectomy by preventing increases in growth hormone receptor (GHR) via ubiquitination, suppressing GH pathway activity. At later times, SOCS2 enhances hepatocyte proliferation by modulating a decrease in serum insulin-like growth factor 1 (IGF-1) that allows GH release from the pituitary. SOCS2, therefore, plays a dual role in modulating the rate of hepatocyte proliferation. In particular, this is the first demonstration of an endogenous mechanism to limit hepatocyte proliferation after injury.     

<Emphasis Type="Italic">Artemisia lerchiana</Emphasis> as a producer of essential oil

Abstrac  The composition of essential oil of Artemisia lerchiana Web. plants growing in Volgograd oblast was studied. Sampling was performed from plots contrasting in climatic and soil characteristics. Essential oil was obtained by hydrodistillation. The content of essential oil in shoot biomass increased gradually during shoot formation, flower bud formation, and flowering beginning and then decreased. The highest content of essential oil varied from 1.1 to 1.5% of plant dry weight at the stage of flower bud formation. More than thirty compounds were identified by gas chromatography-mass spectrometry. The following major components were found: camphor, borneol, bornylacetate, camphene, and 1,8-cineole. Some of compounds (sesquiterpenes and sesquiterpenoids) were identified for the first time. The time-course of accumulation of essential oil components strongly depended on habitat edaphic factors and climatic conditions during the year of sampling. The results permit a conclusion that A. lerchiana is a valuable producer of essential oils. Original Russian Text ? E.B. Kirichenko, Yu.V. Orlova, D.V. Kurilov, 2008, published in Fiziologiya Rastenii, 2008, Vol. 55, No. 6, pp. 934–941.     

Shape analysis of the jaws between two minnow species over ontogeny

This study compares sand shiner (Notropis stramineus ) and silverjaw (Ericymba buccata ) minnows, in terms of the morphological shape changes of the upper, lower, and pharyngeal jaws over ontogeny. These two species of minnows initially feed on midge larvae and undergo an ontogenic prey shift. The traditional morphometrics measured—total length, snout‐to‐vent length, eye diameter, premaxilla length, lower jaw length, gape—were regressed onto total length to test for allometry. Digital pictures were processed with tpsDig and further analyzed with MorphoJ utilizing a regular geometric morphometrics procedure using principle component analyses. We examined gut contents for 16 fish of each species. For the silverjaw minnows, we found all jaw variables to exhibit positive allometric growth with increasing total length, while most of the jaw variables for the sand shiner exhibited negative allometric growth with increasing total length. This correlates with an ontogenic prey shift for both species. Sand shiner minnows have been found to be more omnivorous, feeding on algae later in life, while silverjaw minnows undergo a prey shift to larger invertebrates. These species lack oral dentition causing an increased reliance on the pharyngeal apparatus. Principle component analyses revealed elongation of pharyngeal jaw elements in the silverjaw minnows and a relative shortening and bulking of pharyngeal jaws in the sand shiner minnows. The ontogenic dietary shifts observed in these two species provide possible explanation for the morphological changes over ontogeny in jaw elements, which are likely enabling these species to occupy the same habitat with little niche overlap.     

Comprehensive DNA microarray expression profiles of tumors in tenascin-C-knockout mice

Tenascin-C (TNC), an extracellular matrix glycoprotein, plays a pivotal role in tumor growth. However, the mechanism whereby TNC affects tumor biology remains unclear. To investigate the exact role of TNC in primary tumor growth, a mouse mammary tumor cell line, GLMT1, was first developed. Subsequently, global gene expression in GLMT1-derived tumors was compared between wild-type (WT) and TNC-knockout (TNKO) mice. Tumors in WT mice were significantly larger than those in TNKO mice. DNA microarray analysis revealed 447 up and 667 downregulated in the tumors inoculated into TNKO mice as compared to tumors in WT mice. Validation by quantitative gene expression analysis showed that Tnc, Cxcl1, Cxcl2, and Cxcr2 were significantly upregulated in WT mice. We hypothesize that TNC stimulates the CXCL1/2-CXCR2 pathway involved in cancer cell proliferation.