Use of Growth Indices in Yield Forecast

A model has been developed for forecasting of crop yields in which growth indices of biometrical characters based on two or more periods simultaneously have been utilised. The growth indices are obtained as weighted accumulations of observations on biometrical characters in different periods, weights being respective correlation coefficients between yield and biometrical characters. This model has been found better than the models in use.     

The formation of intracellular crystals in midgut glands of Limnoria lignorum

Certain morphological features of intracellular crystal formation within the midgut glands of Limnoria lignorum (Rathke) have been studied with the electron microscope and cytochemical methods. A correlation has been established between Golgi membranes and formation of the crystals. The Prussian blue reaction reveals quantities of iron localized in the intracellular crystals and in small granular structures seen in the apical region of the cells. These granules can be identified as accumulations of Golgi membranes, with which iron-containing particles are associated. When these membrane configurations are studied with the electron microscope, they can be classified and arranged in an assumed sequence which is thought to represent successive stages in the development of crystals. As the membrane systems become progressively specialized, increasing accumulations of dense granular material appear within their interstices. This material is rich in iron and probably represents the component responsible for the positive Prussian blue reaction. This material also appears to be a precursor substance for iron-containing protein molecules which are synthesized and arranged to make up the crystals. These iron-containing molecules are first deposited in orderly array as double rows of dense particles on certain internal membranes of the specialized Golgi complexes. The membranes later disappear and the particles form definitive crystals by rearrangement into a hexagonal close-packed pattern.     

DUROPHAGOUS PREDATION ON MIDDLE JURASSIC MOLLUSCS, AS EVIDENCED FROM SHELL FRAGMENTATION

Abstract:  Durophagous (shell-crushing) predation is known from the beginning of the Phanerozoic, but it has been suggested that modern intensity was not reached until the Late Cretaceous and Early Cenozoic, when specialized marine durophagous taxa increased in diversity. In this paper, evidence of durophagous predation on Middle Jurassic communities of molluscan prey is presented on the basis of distinct accumulations of fossil remains in the Polish Jura (south-central Poland) that contain characteristic, angular shell fragments with sharp, non-abraded margins. The diverse fossil content of the accumulations studied, consisting of either benthic or nektic/nekto-benthic taxa, indicates that the potential predatory taxon was an opportunistic generalist, most probably fish. On the basis of taphonomic observations, the faunal accumulations are interpreted to represent regurgitated remains (pellets). The common occurrence of such accumulations in the Middle Jurassic clays of the Polish Jura indicates that durophagous predation has been intense since the mid-Mesozoic, at least locally.     

Distribution of extracutaneous melanin pigment in Sparus auratus, Mugil cephalus, and Dicertranchus labrax (Pisces, Teleostei)

The morphological and biochemical characteristics of pigment accumulations found in the kidney, liver, spleen, and mesentery of three different species of teleost fishes have been studied. There are significant differences in number, distribution, and morphology of pigment accumulations in different organs of the three species. Biochemical studies have shown the existence of tyrosinase activity in the mesentery of Mugil cephalus and in the kidney and mesentery of Sparus auratus. No tyrosinase activity was found in any internal organs of Dicertranchus labrax. That activity was assayed using three methods: tyrosine hidroxylation, dopa oxidation, and melanin formation. The morphological and biochemical observations are in agreement. In those organs in which we have demonstrated melanin synthetic activity, the pigment cells are morphologically and like melanophores, while in the organs that show no melanin synthetic activity, the pigment cells resemble macrophages.     

The Formation of Intracellular Crystals in Midgut Glands of Limnoria lignorum

Certain morphological features of intracellular crystal formation within the midgut glands of Limnoria lignorum (Rathke) have been studied with the electron microscope and cytochemical methods. A correlation has been established between Golgi membranes and formation of the crystals. The Prussian blue reaction reveals quantities of iron localized in the intracellular crystals and in small granular structures seen in the apical region of the cells. These granules can be identified as accumulations of Golgi membranes, with which iron-containing particles are associated. When these membrane configurations are studied with the electron microscope, they can be classified and arranged in an assumed sequence which is thought to represent successive stages in the development of crystals. As the membrane systems become progressively specialized, increasing accumulations of dense granular material appear within their interstices. This material is rich in iron and probably represents the component responsible for the positive Prussian blue reaction. This material also appears to be a precursor substance for iron-containing protein molecules which are synthesized and arranged to make up the crystals. These iron-containing molecules are first deposited in orderly array as double rows of dense particles on certain internal membranes of the specialized Golgi complexes. The membranes later disappear and the particles form definitive crystals by rearrangement into a hexagonal close-packed pattern.     

Bacterial, fungal, and algal microfossils in the Lower Proterozoic Baikal region of Siberia (Udokan and Sayany Mountains)

Microfossils from metamorphized Lower Proterozoic deposits of the Udokan Mountains (Naminga Formation) and Sayany Region (Daldarma Formation) are investigated in preparations and petrographic thin sections. They include leucoxenized and ferruginous threads varying in size (50–500 μm) and thread accumulations, which are compared to cyanobacteria. Mineralized thalli probably belong to algae. Small, rounded forms from carbonaceous beds are treated as iron and chemolithotrophic bacteria of stagnant zones of paleobasins. Round or pear-shaped nontransparent forms with projections or several fused forms are described from preparations and identified as fungal microfossils. Similar forms have been recorded in the Lower Proterozoic of Karelia.     

Physiology and pathophysiology of iron in hemoglobin-associated diseases

Iron overload and iron toxicity, whether because of increased absorption or iron loading from repeated transfusions, can be major causes of morbidity and mortality in a number of chronic anemias. Significant advances have been made in our understanding of iron homeostasis over the past decade. At the same time, advances in magnetic resonance imaging have allowed clinicians to monitor and quantify iron concentrations noninvasively in specific organs. Furthermore, effective iron chelators are now available, including preparations that can be taken orally. This has resulted in substantial improvement in mortality and morbidity for patients with severe chronic iron overload. This paper reviews the key points of iron homeostasis and attempts to place clinical observations in patients with transfusional iron overload in context with the current understanding of iron homeostasis in humans.     

Genetic studies on amebocytic accumulations in Biomphalaria glabrata

Four types of spontaneous amebocytic accumulations have been reported in Biomphalaria glabrata. Results of crosses involving snails with and without accumulations suggest that the formation of the amebocytic accumulations is controlled by a polygenic system of inherited factors.     

Local characteristics and interrelations between glands and lymphoid conglomerations in the esophageal wall

Proper glands in 248 total preparations and lymphoid accumulations in 112 preparations have been investigated macro-microscopically in the human oesophageal preparations at various age. The organs have been obtained from 152 corpses of persons died from the death by violence and having no pathological changes in the organs of digestive and immune systems. The lymphoid tissue in the oesophageal wall is presented as accumulations of cells (prenodules++) and as diffusely scattered immune-competent cells. The glands and lymphoid accumulations are oriented as longitudinal rows. The lymphoid tissue accumulations are situated near to the glandular ducts, because the latter can serve as pathways for penetrating antigenic material into the organ's wall. The amount of the glands is maximal mature and elderly age, and that of lymphoid accumulations--at the second childhood. The dimensions of the gland body increase in the cranio-caudal direction, while the lymphoid accumulations, just the reverse, have their maximal dimensions in the upper third of the oesophagus. The gland bodies in places of the organ's anatomical narrowings in the section have more alveoles and are situated nearer to the covering epithelium than the glands in the neighbouring areas of the wall.     

An emerging role for Cullin-3 mediated ubiquitination in sleep and circadian rhythm

Although the neurophysiological correlates of sleep have been thoroughly described, genetic mechanisms that control sleep architecture, long surmised from ethological studies, family histories and clinical observations, have only been investigated during the past decade. Key contributions to the molecular understanding of sleep have come from studies in Drosophila, benefitting from a strong history of circadian rhythm research. For instance, a number of recent papers have highlighted the role of the E3 ubiquitin ligase Cullin-3 in the regulation of circadian rhythm and sleep. We propose that different Cullin-3 substrate adaptors may affect specific molecular pathways and diverse aspects of circadian rhythm and sleep. We have previously shown that mutations in BTBD9, a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor, lead to reduced dopamine, increased locomotion and sleep fragmentation. Here, we propose that Cullin-3 acts together with BTBD9 to limit the accumulation of iron regulatory proteins in conditions of iron deficiency. Our model is consistent with clinical observations implicating iron homeostasis in the pathophysiology of RLS and predicts that lack of BTBD9 leads to misregulation of cellular iron storage, inactivating the critical biosynthetic enzyme Tyrosine Hydroxylase in dopaminergic neurons, with consequent phenotypic effects on sleep.     

Belemnite battlefields

Mass accumulations of belemnite rostra ('belemnite battlefields') are common in Mesozoic sediments, and accumulations of belemnoids are also known from older rocks. Many Recent teuthid species suffer mortality immediately after spawning, and some authors have suggested that belemnite accumulations record a similar phenomenon. Conversely, it is clear that many belemnite battlefields actually formed in an environment of net sediment loss, with current alignment and winnowing. A proposed model for the production of belemnite battlefields involves five possible pathways: post-spawning mortality, catastrophic mass mortality, predation concentration, stratigraphical condensation, and resedimentation. Although accumulations that have not been reworked are rare, it is possible to recognise the generating agents of belemnite accumulations through their intrinsic features. A genetic classification of belemnite battlefields, based on the identified pathways, is tested through field examples in Britain and Antarctica, as well as through published examples. □ Belemnites, fossil accumulations, palaeoecology, Mesozoic, Antarctica, Yorkshire.     

Age-related appearance of tubular aggregates in the skeletal muscle of almost all male inbred mice

Tubular aggregates (TAs) which have been recently observed in a few mouse myopathies are identical to those described in human diseases. In this study we show that TAs are also found in the skeletal muscle of almost all normal inbred mice strains. In these inbred strains of mice the presence of TAs is shown to be related to both age and sex. Nine different muscles were stained with the modified Gomori trichrome method to reveal the general morphology of the muscles. Anti-SERCA1 ATPase was used to confirm that the TAs were in fact accumulations of sarcoplasmic reticulum and anti-MyHC IIB to demonstrate that these accumulations were found exclusively in the type IIB muscle fibers. An ultrastructural study confirmed the observations revealed by light microscopy that the TAs were derived from the sarcoplasmic reticulum. TAs were never observed in female inbred mice and were only found in type IIB glycolytic muscle fibers of male inbred mice. Therefore when analyzing the effect of genetic knock out and knock in experiments on the muscle phenotype of transgenic mice one should be aware that the presence of these aggregates is a non-specific phenomenon induced by inbreeding.     

The role of the mitochondrion in cellular iron homeostasis

The yeast ATM1 protein is essential for normal mitochondrial iron homeostasis. Deletion of ATM1 results in mitochondrial iron accumulation and oxidative mitochondrial damage. Mutations in ABC7, the human homolog of ATM1, result in X-linked sideroblastic anemia and ataxia. Here we show that a deletion of ATM1 also has effects on extra-mitochondrial iron metabolism. ATM1-deficient cells have an increased iron requirement for growth. When grown in iron-rich medium, mutant cells accumulate excess mitochondrial iron and have increased expression of the genes required for both high and low affinity iron uptake. Thus, ATM1 mutant cells simultaneously demonstrate features of both iron overload and iron starvation. Yfh1p is the yeast homolog of the human frataxin protein, which is deficient in Friedreich's ataxia. As in atm1 cells, a yfh1 deletion results in both mitochondrial iron accumulation and cytosolic iron starvation. In spite of their apparent roles in cellular iron homeostasis, we find that the expression of neither ATM1 nor YFH1 is responsive to cellular iron status. Based on these observations, we propose a model in which cellular iron is prioritized for use by the mitochondrion, and available to the remainder of the cell only after mitochondrial needs have been fulfilled.     

Rapid reduction of iron in horse spleen ferritin by thioglycolic acid measured by dispersive X-ray absorption spectroscopy

Summary The release of iron from ferritin is important in the formation of iron proteins and for the management of diseases in both animals and plants associated with abnormal accumulations of ferritin iron. Much more iron can be released experimentally by reduction of the ferric hydrous oxide core than by chelation of Fe³⁺ which has led to the notion that reduction is also the major aspect of iron release in vivo. Variations in the kinetics of reduction of the mineral core of ferritin have been attributed to the redox potential of the reductant, redox properties of the iron core, the structure of the protein coat, the analytical method used to detect Fe²⁺ and reactions at the surface of the mineral. Direct measurements of the oxidation state of the iron during reduction has never been used to analyze the kinetics of reduction, although Mössbauer spectroscopy has been used to confirm the extent of reduction after electrochemical reduction using dispersive X-ray absorption spectroscopy (DXAS). We show that the near edge of X-ray absorption spectra (XANES) can be used to quantify the relative amounts of Fe²⁺ and Fe³⁺ in mixtures of the hydrated ions. Since the nearest neighbors of iron in the ferritin iron core do not change during reduction, XANES can be used to monitor directly the reduction of the ferritin iron core. Previous studies of iron core reduction which measured by Fe²⁺ · bipyridyl formation, or coulometric reduction with different mediators, suggested that rates depended mainly on the redox potential of the electron donor. When DXAS was used to measure the rate of reduction directly, the initial rate was faster than previously measured. Thus, previously measured differences in reduction rates appear to be influenced by the accessibility of Fe²⁺ to the complexing reagent or by the electrochemical mediator. In the later stages of ferritin iron core dissolution, reduction rates drop dramatically whether measured by DXAS or formation of Fe²⁺ complexes. Such results emphasize the heterogeneity of ferritin core structure.     

Radar observations of concentrations of insects above a river in Mali, West Africa

Abstract. 1. Radar observations are reported which demonstrate nocturnal accumulations of insects in the altitude range 30–130 m over some sections of the River Niger.
2. It is shown that on occasions when individual insect tracks were resolved, the accumulations were maintained by positive insect flight manoeuvres, and were not the result of passive response to air movement.
3. The mechanisms by which the insects might perceive the presence of the river are examined and it is deduced that at least some of the insects were able to detect the river boundaries by a visual or radiation sensing mechanism. It is noted that if the insects were using visual perception, their eyes must have been able to function in the absence of moonlight.
4. Evidence is presented which suggests that amongst the insects which contributed to the phenomenon were Ephemeroptera, and also larger insects, the latter becoming concentrated over the river in the course of migratory flight across the area.
5. Reasons why the insects accumulated over the river are discussed and it is suggested that the most probable strategies included the formation of mating swarms by some insects, and the use of the river by others as a linear feature to facilitate their orientation. It is also suggested that the insects may have been responding to differences in infra-red radiation from the river and the bank, or to the warmer, moister air to be expected over the river.     

Nuage morphogenesis becomes more complex: two translocation pathways and two forms of nuage coexist in Drosophila germline syncytia

We have developed a simple and reliable method of preserving antigen immunoreactivity with concomitant excellent retention of the cell ultrastructure. Using this method, we have been able to follow the origin and developmental stages of nuage accumulations within the nurse cell/oocyte syncytium in the ovary of the fruit fly, Drosophila melanogaster, at the ultrastructural level. We have found two morphologically and biochemically distinct forms of nuage material in the nurse cell cytoplasm: translocating accumulations of nuage containing the Vasa protein, termed sponge bodies and stationary polymorphic accumulations of nuage enriched in Argonaute and Survival of motor neuron proteins. Immunogold labeling combined with confocal fluorescent and ultrastructural analyses have revealed that the Vasa-containing nuage accumulations remain closely associated with the cisternae of the endoplasmic reticulum throughout their lifetimes. The migration mechanism of the Vasa-positive nuage appears distinct from the microtubule-dependent translocation of oskar ribonucleoprotein complexes. We postulate that these two distinct nuage translocation pathways converge in the formation of the polar granules within the polar/germ plasm of the oocyte posterior pole. We also provide morphological and immunocytochemical evidence that these polymorphic nuage accumulations correspond to the recently described cytoplasmic domains termed U body-P body complexes.     

Iron speciation study in Hfe knockout mice tissues: Magnetic and ultrastructural characterisation

Liver, spleen and heart tissues of DBA/2 Hfe knockout mice have been characterised by low temperature AC magnetic susceptibility measurements together with Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction in order to investigate the chemical iron speciation in a murine model of iron overload diseases. With emphasis on ferritin-like species, the temperature dependent in-phase and out-of-phase susceptibility profiles agree with the elemental analysis in that, in this model, iron accumulation takes place in the hepatic tissue while in the spleen and heart tissues no differences have been observed between knockout and wild type animals. The comparison of the magnetic properties between perfused and non-perfused liver tissues has made it possible to estimate the magnetic contribution of usually present blood remains. The TEM observations reveal that, besides the isolated ferritins and ferritin-containing lysosomes–siderosomes present in the hepatocytes, other iron deposits, of heterogeneous size, morphology and crystalline structure (haematite and/or goethite), are present in the cytoplasm, near the membrane, and in extracellular spaces.     

Aggregation of Neurofilaments in NF-L Transfected Neuronal Cells: Regeneration of the Filamentous Network by a Protein Kinase C Inhibitor

Abstract: Cytoplasmic inclusion bodies that are accumulations of neurofilaments are the pathological hallmark of many neurodegenerative diseases and have been produced in transgenic mice by overexpression of mouse (NF-L and NF-M; light and medium chains, respectively) and human (NF-M and NF-H; medium and heavy chains, respectively) neurofilament subunits. This report describes a neuronal culture model in which human NF-L was overexpressed to produce cytoplasmic accumulations of neurofilaments within cell bodies concomitant with the collapse of the endogenous neurofilament network. Electron microscopy showed that, within accumulations, neurofilaments retained a filamentous structure. The culture model thus provides a novel system in which the effect on neurofilament accumulations of manipulating protein phosphorylation can be studied. Treatment of cells containing neurofilament accumulations with bisindolylmaleimide, a specific protein kinase C inhibitor, resulted in regeneration of the filamentous network; this effect was not due to a change in the level of transfected NF-L expression. These findings lend support to the suggestion that an impairment in the regulation of protein phosphorylation may lead to the accumulation of neurofilaments seen in neurodegenerative disease.     

Piscine macrophage aggregates: A review

Piscine macrophage aggregates (MAs), alternatively known as melano-macrophage centers (MMC), are focal accumulations of macrophages usually containing the pigments hemosiderin, lipofuscin and ceroid, and melanin. The structures are not confined to fish and have been observed in other poikilothermic vertebrates. The aggregations are most commonly present in the spleen, pronephros, mesonephros and liver but may be found in other organs, especially in relation to inflammation. In the lower fishes (Agnatha, Chondrichthyes) the pigmented cells tend to be solitary or in small (<30 cells/aggregation), irregularly shaped aggregations primarily in hepatic tissue. In the Osteichthyes, greater numbers of cells and aggregates are present than in the lower fishes. These aggregates are more nodular, and they occur more commonly in the spleen and kidney rather than the liver.An exception to these observations if found in the Clupeiformes and the Salmoniformes, considered lower teleosts, who have poorly organized and irregularly shaped aggregations that are smaller than the higher teleosts.Macrophage aggregates function in normal physiological processes and in the body's defense against injurious agents. Evidence indicates that these functions are multiple, complex, and not well understood. They may be classified as, (a) immune, including humoral and inflammatory responses; (b) storage, destruction, or detoxification of exogenous and endogenous substances; and (c) iron recycling. There is a growing body of information that elucidates these functions.Macrophage aggregates qualify as anatomical and cytological biomarkers since they are known to change in number, size, and pigment content in relation to fish health and environmental degradation. Their value lies in their ubiquity, availability, and ease of measurement. There have been few extensive, controlled attempts to produce MAs or to study their kinetics by chronic exposure to contaminants known to exist in polluted environments. Clearly, without such investigations the value of MAs as monitors (biomarkers) of fish health and environmental degradation remains questionable.     

Primary sideroblastic anemia masked by bleeding.

A patient with characteristic features of iron deficiency was unexpectedly found to have circulating siderocytes. Bone marrow iron stain at this time showed absence of both hemosiderin and ringed sideroblasts; electron microscopy revealed absence of mitochondrial iron loading but presence of cytoplasmic ferritin in normoblasts. Replenishment of iron stores led to development of typical sideroblastic anemia. These observations suggest that increased percentage of siderocytes in otherwise typical iron deficiency anemia may signify the presence of a sideroblastic process masked by iron deficiency due to bleeding.