Natural occurrence of Nocardia in soil of Tucumán: Physiological characteristics

This is the first study initiated in Argentina to establish the presence of species of Nocardia from soil samples. These samples were gathered in different areas of Tucumán.Thirty three pathogenic strains of Nocardia were isolated by the paraffin bait method. Out of them, 28 were N. brasiliensis, 3 N. asteroides and 2 N. caviae. N. brasiliensis was widely distributed in the soil of the areas tested.It is proved that N. caviae, so rarely found in other regions of the world, occurs in Tucumán.A detailed study of the morphological and physiological characteristics for identification is discussed.     

Bakkeius moragai n. gen. et n. sp. and Pojmanskia riosae n. gen. et n. sp. (Trematoda: Digenea: Brachylaimoidea) in birds from the Area de Conservación Guanacaste, Costa Rica

We describe 2 new species of leucochloridiid-like brachylaimoid digeneans parasitizing a variety of birds in the Area de Conservación Guanacaste, Costa Rica, each of which we assign to a new genus. According to Pojmanska's (Pojmanska, T. 2002a. Superfamily Brachylaimoidea Joyeux & Foley, 1930. In Keys to the Trematoda, D. I. Gibson, A. Jones, and R. A. Bray [eds.]. CAB International and The Natural History Museum, London, U.K., p. 31-36.) key for the Brachylaimoidea, we are unable to place either species in any family. One species most closely resembles members of Leucochloridium by having well-developed suckers, lacking an esophagus, and having cecal shoulders, gonads at the posterior end, and the genital pore at posterior end of body but differs by having symmetrical testes, a posttesticular ovary, and a terminal genital pore; thus, we propose the genus Bakkeius for it. The second new genus resembles members of Michajlovia by having ventral genital pores but differs by having extracecal uterine loops in the forebody, a cirrus sac containing the pars prostatica and seminal vesicle, and gland cells surrounding the genital pore; thus, we propose Pojmanskia for it. These new genera must currently be treated as incertae sedis according to Pojmanska (op. cit.); however, we feel that future phylogenetic analyses will require emendation of the family diagnosis for Leucochloridiidae to include those taxa with terminal and ventral genital pores and with preovarian testes.     

Nitrous oxide reduction in nodules: denitrification or n(2) fixation?

Detached cowpea nodules that contained a nitrous oxide reductase-positive (Nor) rhizobium strain (8A55) and a nitrous oxide reductase-negative (Nor) rhizobium strain (32H1) were incubated with 1% N(2)O (95 atom% N) in the following three atmospheres: (i) aerobic with C(2)H(2) (10%), (ii) aerobic without C(2)H(2), and (iii) anaerobic (argon atmosphere) without C(2)H(2). The greatest production of N(2) occurred anaerobically with 8A55, yet very little was formed with 32H1. Although acetylene reduction activity was slightly higher with 32H1, about 10 times more N(2) was produced aerobically by 8A55 than by 32H1 in the absence of acetylene. The major reductive pathway of N(2)O reduction by denitrifying rhizobium strain 8A55 is by nitrous oxide reductase rather than nitrogenase.     

Clitellocephalus americanus n. gen., n. sp. (Apicomplexa: Eugregarinida: Gregarinidae) from Cratacanthus dubius (Coleoptera: Carabidae: Harpalinae) in the Nebraska sandhills and Clitellocephalus ophoni n. comb. (Apicomplexa: Eugregarinida: Gregarinidae) from Ophonus pubescens (Coleoptera: Carabidae: Harpalinae) in Sète,France

Clitellocephalus americanus n. gen., n. sp. (Apicomplexa: Eugregarinida: Gregarinidae) is described from Cratacanthus dubius (Coleoptera: Carabidae) collected from Keith County in the Sandhills of western Nebraska. Clitellocephalus ophoni n. comb. is redescribed using original type material from Ophonus pubescens (Coleoptera: Carabidae) collected in Sète, France. Clitellocephalus n. gen. is distinguished by a deltoid epimerite with an internal anterior obconoid structure and a basal toroidal vacuole, which is retained in gamonts. Protomerites are broadly elliptical to cylindrical; deutomerites are narrowly obovate. Association is precocious, caudofrontal, and biassociative, with the satellite protomerite engulfing the posterior end of the primite deutomerite to form an interlock. Gametocysts are spherical. Sporoducts are present but reduced and irregular in number. Oocysts are dolioform, dehiscing in chains. The species described herein are differentiated by their overall size and relative proportion of cellular structures.     

Neohaematotrephus arayae n. sp. (Digenea: Echinostomiformes: Cyclocoelidae) in Jacana spinosa (Aves: Charadriiformes: Jacanidae) from the Area de Conservación Guanacaste, Costa Rica

Specimens of a species of cyclocoelid digenean inhabiting Jacana spinosa from the Area de Conservación Guanacaste, Costa Rica, most closely resemble Haematotrephus facioi (Brenes and Arroyo, 1962) Yamaguti, 1971, in the same host from Aranjuez, Puntarenas Province, Costa Rica, in having confluent vitelline follicles posteriorly, diagnostic of Neohaematotrophus, and in pharynx length, ovary width, and cirrus sac on the sinistral side. The new species is also highly similar in appearance to H. gendrei Dubois, 1959, also inhabiting a jacanid (from West Africa), which has vitelline follicles confluent posteriorly, and extending anteriorly to the intestinal bifurcation and genital pore opening immediately posterior to the anterior margin of the pharynx. Like H. facioi, H. gendrei has a relatively much shorter and broader cirrus sac than does the new species. Examination of the holotype and paratype of H. facioi confirmed that the specimens from Guanacaste differ in having a longer body, a larger ovary and eggs, and smaller testes. They also have the ovary on the sinistral rather than the dextral side of the body, genital pore anterior to the pharynx rather than at or posterior to the level of the posterior margin of the pharynx, longer and thinner cirrus sac, and eggs without eyespotted miracidia. Half the eggs in both specimens of H. facioi have well-developed eyespotted miracidia, whereas the typical condition for cyclocoelids is for virtually all eggs to exhibit eyespotted miracidia. Both H. facioi and H. gendrei are transferred to Neohaematotrophus, along with the new species.     

Osteosarcopenia: una revisión narrativa

Osteosarcopenia is a phenotype resulting from the combination of sarcopenia and low bone mineral density. Based on the relationship between bone and muscle, this phenotype is associated with a higher risk of falls, fractures, dependence, and health care costs than its individual components. Given its characteristics, it can be considered as a new geriatric syndrome. Therefore, understanding its pathophysiology and diagnosis, as well as its non-pharmacological and pharmacological management is a task of great importance. The problem in addressing this phenotype arises from the tradition of managing sarcopenia and osteoporosis separately. There is also a lack of consensus on what to call it (sarco-osteopenia, sarco-osteoporosis, osteosarcopenia). The aim of this review is to outline the epidemiology, pathophysiology, diagnoses, adverse events, and management of osteosarcopenia.     

Paracreptotrema blancoi n. gen., n. sp. (Digenea: Plagiorchiformes: Allocreadiidae) in the Olomina, Priapichthys annectens (Osteichthyes: poeciliidae), from the Area de Conservación Guanacaste, Costa Rica

A new species of allocreadiid digenean is described from Priapichthys annectens (Regan) (Osteichthyes: Poeciliidae) in the Area de Conservación Guanacaste, Costa Rica. A new genus, Paracreptotrema, is proposed to accommodate this species as well as Fellodistomum mendezi Songandares-Bernal, 1955, which was previously described from another poeciliid, Brachyrhaphis episcopi, in Panama. Paracreptotrema differs from all other nominal genera of Allocreadiidae by a combination of its symmetrical testes, restricted vitellaria, and the lack of oral lappets (muscular 'papillae') or other such appendages. Paracreptotrema blancoi n. sp. resembles Creptotrema creptotrema Travassos, Artigas and Pereira, 1928, but differs in lacking ventral oral lappets and in having vitellaria extending posteriorly only to the level of the testes. It can be distinguished from P. mendezi n. comb. in having a relatively larger and more posteriorly placed acetabulum, vitellaria that are more restricted anteriorly, smaller testes, and a uterus that does not extend to the posterior end of the body. The genus seems to be restricted to poeciliids in Central America.     

History and evolution of the arctic flora: in the footsteps of Eric Hultén

A major contribution to our initial understanding of the origin, history and biogeography of the present-day arctic flora was made by Eric Hultén in his landmark book Outline of the History of Arctic and Boreal Biota during the Quarternary Period, published in 1937. Here we review recent molecular and fossil evidence that has tested some of Hultén's proposals. There is now excellent fossil, molecular and phytogeographical evidence to support Hultén's proposal that Beringia was a major northern refugium for arctic plants throughout the Quaternary. In contrast, most molecular evidence fails to support his proposal that contemporary east and west Atlantic populations of circumarctic and amphi-Atlantic species have been separated throughout the Quaternary. In fact, populations of these species from opposite sides of the Atlantic are normally genetically very similar, thus the North Atlantic does not appear to have been a strong barrier to their dispersal during the Quaternary. Hultén made no detailed proposals on mechanisms of speciation in the Arctic; however, molecular studies have confirmed that many arctic plants are allopolyploid, and some of them most probably originated during the Holocene. Recurrent formation of polyploids from differentiated diploid or more low-ploid populations provides one explanation for the intriguing taxonomic complexity of the arctic flora, also noted by Hultén. In addition, population fragmentation during glacial periods may have lead to the formation of new sibling species at the diploid level. Despite the progress made since Hultén wrote his book, there remain large gaps in our knowledge of the history of the arctic flora, especially about the origins of the founding stocks of this flora which first appeared in the Arctic at the end of the Pliocene (approximately 3 Ma). Comprehensive analyses of the molecular phylogeography of arctic taxa and their relatives together with detailed fossil studies are required to fill these gaps.     

Simplified Bayesian method: application in cytogenetic biological dosimetry of mixed n + γ radiation fields

This article describes the application of a simplified Bayesian method for estimation of doses from a mixed field using cytogenetic biological dosimetry, taking as an example neutron and gamma radiation emitted from the MARIA nuclear research reactor in Poland. The Bayesian approach is a good alternative to the commonly used iterative method, which allows separate dose estimation. In the present paper, a computer program, which uses the iterative and simplified Bayesian methods to calculate mixed radiation doses, is introduced.

     

Sahelian woody vegetation in Sénégal

Structure and composition of woody vegetation in Sahelian forest types (not including riparian and riverine types) were studied in Sénégal. The application of classification and ordination resulted in the recognition of seven distinctive woody community types, related to soil and precipitation gradients. The described vegetation types only contained four strictly Saharan species, the rest being of Sahelian and Soudanean affinity, so a floristic change from savanna to desert vegetation after two decades of drought could not be confirmed. Tree density was lower in the northern part than earlier, possibly an indication of degradation. Rejuvenation was greatest at the northernmost arenosolic stations, but low in the southern, ferrouginous areas. This presumably demonstrates the resilience of North-Sahelian vegetation, at the moment being in a dynamic rejuvenation phase, after a period of adverse conditions.     

Phytoplankton biomass in Lake Xolotlán (Managua): Its seasonal and horizontal distribution

Some well-documented studies on restoring eutrophic lake systems in The Netherlands by fish stock management have been evaluated with the emphasis on the role of macrophytes. Furthermore, the factors determining the light climate for submerged macrophytes in a large shallow eutrophic lake (Lake Veluwe) have been assessed and the potential success of biomanipulation in large scale projects is discussed. Today relatively little attention has been paid to macrophyte management although the importance of macrophytes in lake restoration has been recognized regularly. The biomanipulation strategy was successful in small scale projects. In a large scale project, however, wind-induced resuspension may largely determine the underwater light climate through attenuation by the water column and periphytic layer. Therefore, restoration of relatively large waterbodies by fish stock management only is expected not to lead to any noteworthy improvement of the light climate for submerged macrophytes. Additional measures aimed at reducing wind-induced resuspension of sediment particles and reestablishing of the macrophyte stands are required for successful biomanipulation strategies. Water quality managers should pay more attention to macrophyte stands in biomanipulation projects because macrophytes enhance a more stable and diverse ecosystem. Restoration objectives and the methods of their achievement must be carefully planned since an abundant submerged macrophyte vegetation may have undesirable effects as well.     

Phosphorus in acidified lakes: The example of Lake Gårdsjön,Sweden

Supply and turnover of phosphorus was studied in an acidified lake ecosystem, Lake Gårdsjön, located in southwestern Sweden. This study included transport and budget calculations combined with field and laboratory experimental work on abiotic phosphorus chemistry and biological utilization of phosphorus. The main conclusions presented in this paper are:

- The acidification process in inland waters resulting from acid atmospheric deposition is accompanied by ‘oligotrophication’ because of reduced input of phosphorus from the drainage area, possibly due to efficient fixation of phosphorus to aluminium complexes in the B-horizon of podzol soils

- Primary productivity in acidified lakes is limited mainly by low phosphorus supply

- Algal utilization of phosphorus in acidified lakes is impaired, yielding lower biomass than could be expected from ambient phosphorus concentrations. One possible reason for this could be that enzymatic recycling of organic phosphates is prevented by high levels of aluminium in lake water.

     

Tinamutrema canoae n. gen. et n. sp. (Trematoda: Digenea: Strigeiformes: Brachylaimidae) in Crypturellus cinnamomeus (Aves, Passeriformes, Tinamidae) from the Area de Conservación Guanacaste, Costa Rica

We propose Tinamutrema as a new genus for Brachylaima centrodes (Braun, 1901) Dollfus, 1935 and for T. canoae, as a new species inhabiting tinamus in the Area de Conservación Guanacaste, Costa Rica. Specimens from Costa Rica resemble B. centrodes in having an elongate body, pretesticular genital pore and terminal genitalia, intercecal uterine loops occupying all available space between the anterior testis and the intestinal bifurcation, an oral sucker width:pharynx width ratio of approximately 1:0.55, an oral sucker:ventral sucker width ratio of approximately 1:1, and vitelline follicles extending into the forebody closer to the pharynx than to the anterior margin of the ventral sucker and by living in the cloaca. They differ from B. centrodes in having vitelline follicles that do not extend as far anteriorly as those in B. centrodes, which extend anteriorly to the level of the anteriormost extent of the cecal "shoulders," dense tegumental spination as opposed to sparse or no spination, relatively smaller cirrus with fewer spines, longer and more sinous pars prostatica, and forebody averaging 36% of total body length (TBL) as opposed to 42% TBL. Both species differ from other members of the Brachylaimidae in possessing a spinose cirrus and a cirrus sac containing both the cirrus and the pars prostatica. Preliminary phylogenetic assessment suggests that these traits are plesiomorphic, and thus the species are basal to the rest of the Brachylaimidae, whose diagnosis we emend accordingly.     

Hourly activity of Lutzomyia neivai in the endemic zone of cutaneous leishmaniasis in Tucumán, Argentina: preliminary results

In the present work, the hourly activity of Lutzomyia neivai was studied in the southern part of the province of Tucumán, Argentina, in an area of transmission of cutaneous leishmaniasis during two months of higher activity. In addition, the variables that influenced the abundance of Lu. neivai were evaluated. A total of 1,146 individuals belonging to Lu. neivai (97%) and Lutzomyia migonei (3%) were captured. The hourly activity of Lu. neivai was mainly nocturnal, with a bimodal pattern in both months. In January, the variable that most influenced the abundance of Lu. neivai was the temperature, whereas in April, that variable was humidity. These results may contribute to the design of anti-vectorial control measures at a micro-focal scale.     

Polymorphic microsatellites in nēnē, the endangered Hawaiian goose (Branta sandvicensis)

The nēnē (Branta sandvicensis) is an endangered Hawaiian goose endemic to the Hawaiian Islands. The nēnē nearly went extinct in the mid-19.00s and the majority of the approximately 1300 individuals currently in Hawai'i are descendants from less than 30 birds. The low adult breeding success and juvenile survival is likely due, in part, to inbreeding depression in wild individuals. Thirty-eight microsatellite primer sets developed in nēnē, Canada goose, and waterfowl species provided 8 polymorphic loci. Four of these polymorphic loci exhibited only two alleles, which is likely a reflection of the high inbreeding in this species.     

Parallopharynxs pp. (Trematoda: Digenea: Plagiorchioidea) in iguanian lizards from the Area de Conservación Guanacaste, Guanacaste, Costa Rica, including Parallopharynx matternae n. sp. in Chaetodon basiliscus (Squamata: Iguania: Corytophanidae)

We report 3 species of the digenean genus Parallopharynx, 1 previously undescribed, from the Area de Conservación Guanacaste (ACG) in northwestern Costa Rica. Parallopharynx gonzalezi, which was originally described in Basiliscus sp. and Ctenosoura similis from central Costa Rica, inhabits C. quinquecarinata; P. jonesi, originally described in Anolis lionotus (syn. Norops oxylophus) from Nicaragua, inhabits N. oxylophus, N. biporcatus, and Basiliscus basiliscus; and the new species, which inhabits B. basiliscus. Parallopharynx matternae n. sp. differs from all other members of the genus by having a metraterm extending posteriad from the genital pore to the posterior margin of the ventral sucker, whereas in P. arctus and P. gonzalezi, the metraterm never surpasses the midlevel of the ventral sucker and in P. jonesi it never passes the anterior margin of the ventral sucker, and by having an oral sucker that does not exceed 150 microm in diameter with a subsequent greater oral-ventral sucker width ratio ranging from 1:0.88-1.12 (averaging 1:1), whereas values range from 1:0.71-0.83 for P. gonzalezi and P. arctus, and from 1:0.59-0.68 for P. jonesi. Parallopharynx spp. possesses Y-shaped excretory vesicles with a long central stem and short arms bifurcating immediately posterior to the ovary; similar to those found in members of the Telorchiidae. Additional similarities in the relative positions of the gonads and the structure of the cirrus sac and metraterm indicate a close relationship between Parallopharynx and members of the Telorchiidae.     

Sayil Revisited: Inferring Terminal Classic Population Size and Dynamics in the West-Central Yucatán Peninsula

Research at the site of Sayil in the Yucatan Peninsula has provided a valuable database for making inferences about the Terminal Classic (A.D. 750–1000) occupation of the Puuc region. This article evaluates and modifies previous demographic estimates for the site and considers the long-term implications associated with supporting this many people. Although a relatively high level of population was possible because of the excellent soils in the region, their natural fertility could not have been sustained indefinitely. The apparent demographic load on the proposed Sayil system would have required an intensive cropping strategy that may not have been sustainable for more than 75 years. This conclusion not only indicates how long the principal occupation of Sayil may have lasted, but more importantly, how the occupational dynamics during the Terminal Classic may have played out in the greater Puuc region.     

Herbivory in a fragmented tropical forest: patterns from islands at Lago Gatún, Panama

By imposing density-dependent mortality upon their hosts, specialistinsect herbivores are thought to contribute to the maintenance of tree diversityin tropical forests. Forest fragmentation may alter patterns of herbivory,however, which may have important implications for tree species diversity inforest remnants. To explore effects of fragmentation on patterns of herbivory,we assessed folivory by Lepidopteran larvae on saplings of four focal treespecies on eight artificial, forested islands at Lago Gatún, Panama. Weexplored the importance of island area, distance to larger land, exposure to dryseason winds, tree species, and season in determining proportions of new leavesdamaged by caterpillars, and proportions of leaf area lost to caterpillars,during two dry and wet seasons. We found that both measures of herbivoryincreased markedly with island area, that island isolation had no apparenteffect on herbivory, and that interactions between season and exposure, andbetween tree species and season, were important determinants of herbivory rates.In addition, we observed species-specific differences in herbivory among hostplants under various conditions imposed by fragmentation. We conclude thatpatterns of herbivory by Lepidopteran larvae are sensitive to fragmentation inthis tropical forest. Differential herbivory among the four tree speciesconsidered here may have important implications for tree species dynamics on theislands of Lago Gatún.