Tropical pyomyositis of the abdominal wall musculature mimicking acute abdomen.

Hemochromatosis is an autosomal recessive genetic disorder that occurs with high prevalence in populations of European origin. The gene that is abnormal in hemochromatosis is found on the short arm of chromosome 6 in close proximity (approximately 1 centimorgan) to HLA-A, but the product coded for by that gene is unknown. The pathogenetic mechanism in hemochromatosis is that of continued, excessive absorption of dietary iron with loss of normal control mechanisms, leading to a gradual but vast expansion of storage iron as ferritin and especially as hemosiderin. Through mechanisms that probably include peroxidation of lipid membranes, the excess iron injures hepatocytes, islet B cells, gonadotropes in the anterior pituitary, myocardium, synovial cells, and chondrocytes, and probably other cells and tissues as well. Most patients with hemochromatosis remain undiagnosed throughout life. Removal of the excess iron by phlebotomy will prevent all of the complications of hemochromatosis when begun early and will significantly improve survival in virtually all patients. It is important, therefore, that the diagnosis of hemochromatosis be considered much more frequently in clinical medicine in order that this effective therapy be utilized.     

Temperate phages of Clostridium perfringens type C1.

Four phages isolated from carrier strains of Clostridium perfringens type C belong to two classes. The three phages of class I, c1, c3, and c4, and homoimmune and serologically closely related. The phage of class II, c5, is heteroimmune to the class I phages and not related to them serologically. Transduction experiments with several of the phages were negative. Mutants of the indicator strain with surface alterations occurred spontaneously in stock cultures. Electron micrographs show the phages of each class to be distinct yet similar, having polyhedral heads of about the same diameter 55 nm, and long, flexible tails without sheaths or collars. Phages c4 and c5 were characterized for their lysogenic properties. Phage c4 was inducible with mitomycin C. Both c4 and c5 were temperate viruses by the test of stability of their respective lysogens to phage-specific antisera.     

A review of the Temperate Broad-Leaved Evergreen Forest zone of southeastern North America: Floristic affinities and arborescent vegetation types

The Temperate Broad-Leaved Evergreen Forest (TBEF) zone is centered in peninsular Florida. It is characterized by mainly nontropical taxa that form an evergreen dicot forest, often with aSabal palm in the canopy, in which deciduous dicot trees are present but rarely become local dominants. The Madrean-Tethyan floristic affinities of this life zone are briefly discussed, as is plant endemism, and a recommendation is given for recognizing it as a separate phytochorion, the Central Floridian Subprovince, in the Atlantic and Gulf Coastal Plains Province of southeastern North America. Also recommended for separate status is the Apalachicolan Subprovince, in the panhandle of Florida and adjacent Georgia and Alabama. These recommendations follow an earlier recognition of the floristic uniqueness of both areas (Greller, 2000). Three physiographical regions in the TBEF are recognized: Peninsular Florida (including the Atlantic and Gulf Coastal regions); the Atlantic Outer Coastal Plain, Sea Islands and Outer Banks; and the Gulf Coastal Shores, Islands, Prairies and Marshes (from panhandle Florida west to Louisiana and Texas). Following Heinrich Walter’s zonobiome classification system, one zonobiome and two zonoecotones are recognized for the TBEF region. Following a literature review, a classification of TBEF ligneous, mainly arborescent, vegetation types is given. The article ends with brief discussions of some lowland and a number of montane arborescent vegetation types of the Greater Antilles and of Baja California related to TBEF flora and vegetation.     

Himalayan langurs: Temperate colobines

Four field studies of the langur monkey, Presbytis entellus, living in the Himalaya are compared, in order to uncover shared features of behavior and population structure that may be related to this habitat. Shared demographic characteristics include seasonality in mating and births, predominately multi-male troops at least during some times of the year, relatively large home ranges, low population densities with few intertroop encounters, and seasonal utilization of home ranges with distance maintenance between groups. Shared social characteristics include behavioral buffers against cold and inclement weather, fluctuation in male membership with greatest instability and lowest numbers during the mating season, a vocal repertoire marked by a unique vocalization of major importance in troop maintenance as well as alterations in the function of species-typical vocalizations, and variations in sexual behavior including variable expression of “typical” female headshake present, increased male initiation of sexual activity and a low incidence of female harrassment of sexual consorts. It is argued that while no single feature may be unique to Himalayan langur populations, the total cluster of features is, and can be related to climatic seasonality in the Himalayan temperate environment, the predominance of a multi-male group structure for some periods, and possibly genetic isolation.     

Plant-soil Interactions in Temperate Grasslands

We present a conceptual model in which plant-soil interactions in grasslands are characterized by the extent to which water is limiting. Plant-soil interactions in dry grasslands, those dominated by water limitation (belowground-dominance), are fundamentally different from plant-soil interactions in subhumid grasslands, where resource limitations vary in time and space among water, nitrogen, and light (indeterminate dominance). In the belowground-dominance grasslands, the strong limitation of soil water leads to complete (though uneven) occupation of the soil by roots, but insufficient resources to support continuous aboveground plant cover. Discontinuous aboveground plant cover leads to strong biological and physical forces that result in the accumulation of soil materials beneath individual plants in resource islands. The degree of accumulation in these resource islands is strongly influenced by plant functional type (lifespan, growth form, root:shoot ratio, photosynthetic pathway), with the largest resource islands accumulating under perennial bunchgrasses. Resource islands develop over decadal time scales, but may be reduced to the level of bare ground following death of an individual plant in as little as 3 years. These resource islands may have a great deal of significance as an index of recovery from disturbance, an indicator of ecosystem stability or harbinger of desertification, or may be significant because of possible feedbacks to plant establishment. In the grasslands in which the dominant resource limiting plant community dynamics is indeterminate, plant cover is relatively continuous, and thus the major force in plant-soil interactions is related to the feedbacks among plant biomass production, litter quality and nutrient availability. With increasing precipitation, the over-riding importance of water as a limiting factor diminishes, and four other factors become important in determining plant community and ecosystem dynamics: soil nitrogen, herbivory, fire, and light. Thus, several different strategies for competing for resources are present in this portion of the gradient. These strategies are represented by different plant traits, for example root:shoot allocation, height and photosynthetic pathway type (C3 vs. C4) and nitrogen fixation, each of which has a different influence on litter quality and thus nutrient availability. Recent work has indicated that there are strong feedbacks between plant community structure, diversity, and soil attributes including nitrogen availability and carbon storage. Across both types of grasslands, there is strong evidence that human forces that alter plant community structure, such as invasions by nonnative annual plants or changes in grazing or fire regime, alters the pattern, quantity, and quality of soil organic matter in grassland ecosystems. The reverse influence of soils on plant communities is also strong; in turn, alterations of soil nutrient supply in grasslands can have major influences on plant species composition, plant diversity, and primary productivity.     

Temperate forests of the southern hemisphere

The much higher proportion of sea to land in the southern hemisphere creates conditions favouring temperate rain forest on west-facing coasts, so that forests dominated by Nothofagus spp. and southern conifers in Araucariaceae and Podocarpaceae have survived since Cretaceous times. By contrast only Australia preserves to any significant extent forests of a xeromorphic character in drier areas. During the progressive desiccation of the Tertiary era, the prevalent nutrient deficiency in Australian soils led to the evolution of xeromorphic forests of a pronouncedly sclerophyll type in which many elements were inherently fire-resistant. Such forests were enabled to withstand the intensification of burning following the arrival of early man, with selection for the more highly fire-resistant elements such as Eucalyptus which became widely dominant. In other land areas of the southern hemisphere fire has largely destroyed the drier forests.     

Methane Metabolism in a Temperate Swamp

Comparisons between in situ CH₄ concentration and potential factors controlling its net production were made in a temperate swamp. Seasonal measurements of water table level and depth profiles of pH, dissolved CH₄, CO₂, O₂, SO₄^2-, NO₃^-, formate, acetate, propionate, and butyrate were made at two adjacent sites 1.5 to 2 m apart. Dissolved CH₄ was inversely correlated to O₂ and, in general, to NO₃^- and SO₄^2-, potential inhibitors of methanogenesis. At low water table levels (August 1992), maximal CH₄ (2 to 4 μM) occurred below 30 cm, whereas at high water table levels (October 1992) or under flooded conditions (May 1993), CH₄ maxima (4 to 55 μM) occurred in the top 10 to 20 cm. Higher CH₄ concentrations were likely supported by inputs of fresh organic matter from decaying leaf litter, as suggested by high acetate and propionate concentrations (25 to 100 μM) in one of the sites in fall and spring. Measurements of potential CH₄ production (and consumption) showed that the highest rates generally occurred in the top 10 cm of soil. Soil slurry incubations confirmed the importance of organic matter to CH₄ production but also showed that competition for substrates by nonmethanogenic microorganisms could greatly attenuate its effect.     

Temperate forests in continental East Asia

In this editorial, we introduce a Special Feature focusing on various aspects of temperate forest vegetation on the East Asian mainland (China and Korea). The papers included in this Special Feature encompass a range of topics, including plot-based vegetation survey, analysis of vegetation change along broad-scale environmental gradients and dynamics of both successional and climax forests.     

Temperate and tropical algal-sea anemone symbioses

Abstract. In this review, we seek to develop new insights about the nature of algal‐sea anemone symbioses by comparing such associations in temperate and tropical seas. Temperate seas undergo pronounced seasonal cycles in irradiance, temperature, and nutrients, while high irradiance, high temperature, and low nutrients are seasonally far less variable in tropical seas. We compare the nature of symbiosis between sea anemones (= actinians) and zooxanthellae (Symbiodinium spp.) in both regions to test tropical paradigms against temperate examples and to identify directions for future research. Although fewer anemone species are symbiotic in temperate regions, they are locally dominant and ecologically important members of the benthic community compared to the tropics. Zooxanthella densities tend to be lower in temperate anemones, but data are limited to a few species in both temperate and tropical seas. Zooxanthella densities are far more stable over time in temperate anemones than in tropical anemones, suggesting that temperate symbioses are more resistant to fluctuations in environmental parameters such as irradiance and temperature. Light‐saturated photosynthetic rates of temperate and tropical zooxanthellae are similar, but temperate anemone hosts receive severely reduced carbon supplies from zooxanthellae during winter months when light is reduced. Symbiont transmission modes and specificity do not show any trends among anemones in tropical vs. temperate seas. Our review indicates the need for the following: (1) Investigations of other temperate and tropical symbiotic anemone species to assess the generality of trends seen in a few “model’ anemones. (2) Attention to the field ecology of temperate and tropical algal‐anemone symbioses, for example, how symbioses function under seasonally variable environmental factors and how zooxanthellae persist at high densities in darkness and winter. The greater stability of zooxanthella populations in temperate hosts may be useful to understanding tropical symbioses in which bleaching (loss of zooxanthellae) is of major concern. (3) Study of the evolutionary history of symbiosis in both temperate and tropical seas. Continued exploration of the phylogenetic relationships between host anemones and zooxanthella strains may show how and why zooxanthellae differ in anemone hosts in both environments.     

Temperate Bacillus bacteriophage SP16 genome is circularly permuted and terminally redundant.

The physical nature of temperate Bacillus bacteriophage SP16 DNA was analyzed by electron microscopy, exonuclease digestion, denaturation-renaturation experiments, and restriction enzyme analysis. The SP16 genome is a linear molecule 60.0 +/- 2.0 kilobases in length without cohesive ends. Electron micrographs of denatured and renatured SP16 DNA showed that the DNA is circularly permuted. The genome possesses terminal redundancy, as demonstrated by electron microscopy of exonuclease III-digested DNA.     

Nitrogen Metabolism Genes from Temperate Marine Sediments

In this study, we analysed metagenomes along with biogeochemical profiles from Skagerrak (SK) and Bothnian Bay (BB) sediments, to trace the prevailing nitrogen pathways. NO₃ ^? was present in the top 5 cm below the sediment-water interface at both sites. NH₄ ⁺ increased with depth below 5 cm where it overlapped with the NO₃ ^? zone. Steady-state modelling of NO₃ ^? and NH₄ ⁺ porewater profiles indicates zones of net nitrogen species transformations. Bacterial protease and hydratase genes appeared to make up the bulk of total ammonification genes. Genes involved in ammonia oxidation (amo, hao), denitrification (nir, nor), dissimilatory NO₃ ^? reduction to NH₄ ⁺ (nfr and otr) and in both of the latter two pathways (nar, nap) were also present. Results show ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) are similarly abundant in both sediments. Also, denitrification genes appeared more abundant than DNRA genes. 16S rRNA gene analysis showed that the relative abundance of the nitrifying group Nitrosopumilales and other groups involved in nitrification and denitrification (Nitrobacter, Nitrosomonas, Nitrospira, Nitrosococcus and Nitrosomonas) appeared less abundant in SK sediments compared to BB sediments. Beggiatoa and Thiothrix 16S rRNA genes were also present, suggesting chemolithoautotrophic NO₃ ^? reduction to NO₂ ^? or NH₄ ⁺ as a possible pathway. Our results show the metabolic potential for ammonification, nitrification, DNRA and denitrification activities in North Sea and Baltic Sea sediments.     

Redox-Specialized Bacterioplankton Metacommunity in a Temperate Estuary

This study explored the spatiotemporal dynamics of the bacterioplankton community composition in the Gulf of Finland (easternmost sub-basin of the Baltic Sea) based on phylogenetic analysis of 16S rDNA sequences acquired from community samples via pyrosequencing. Investigations of bacterioplankton in hydrographically complex systems provide good insight into the strategies by which microbes deal with spatiotemporal hydrographic gradients, as demonstrated by our research. Many ribotypes were closely affiliated with sequences isolated from environments with similar steep physiochemical gradients and/or seasonal changes, including seasonally anoxic estuaries. Hence, one of the main conclusions of this study is that marine ecosystems where oxygen and salinity gradients co-occur can be considered a habitat for a cosmopolitan metacommunity consisting of specialized groups occupying niches universal to such environments throughout the world. These niches revolve around functional capabilities to utilize different electron receptors and donors (including trace metal and single carbon compounds). On the other hand, temporal shifts in the bacterioplankton community composition at the surface layer were mainly connected to the seasonal succession of phytoplankton and the inflow of freshwater species. We also conclude that many relatively abundant populations are indigenous and well-established in the area.