Diversity, Risk Mediation, and Change in a Trans-Himalayan Agropastoral System

We describe the diversity and dynamism of social, agricultural, and livestock husbandry practices in a traditional mountain production system in the Indian Trans-Himalaya. These are interpreted in the context of their role in mediating environmental risk. The production system is a little known Buddhist agropastoral system in the high altitude Spiti Valley (agriculture up to 4450 m, livestock grazing 4900 m, total area ca. 12,000 km²) in the Himalayan state of Himachal Pradesh. The local population (ca. 10,000) belongs to one of the three Buddhist sects Gelukpa, Shakyapa, or Ningmapa, is related by blood, and shares a common Tibetan dialect. Family is the basic unit of production, though families are highly dependent upon the community to meet production goals. A village council appointed on rotation and functioning democratically is responsible for village administration, and is the arbiter of all decision-making pertaining to collective work and settling disputes. The council ensures equal access of families to common resources, as well as equitable distribution of responsibilities among them. Systems of primogeniture, celibacy, and polygamy seem to have prevented the fragmentation of land holdings and limited population growth. The diversity of practices in the agropastoral system seems adapted to the risk-prone mountainous environment, the risks being climatic, geological, and those posed by wildlife. The system seems to aim at maximizing production while mediating environmental risk. The production system comes forth as highly dynamic, characterized by continuous innovation and experimentation. Recent changes in the production system are in response to both changes in local conditions as well as increasing integration of the local economy with regional markets, though many aspects of the traditional lifestyle continue to be maintained.     

The tomato gene Sw5 is a member of the coiled coil,nucleotide binding,leucine-rich repeat class of plant resistance genes and confers resistance to TSWV in tobacco

Tomato spotted wilt virus is an important threat to tomato production worldwide. A single dominant resistance gene locus, Sw5, originating from Lycopersicon peruvianum, has been identified and introgressed in cultivated tomato plants. Here we present the genomic organization of a 35 250 bp fragment of a BAC clone overlapping the Sw5 locus. Two highly homologous (95%) resistance gene candidates were identified within 40 kb of the CT220 marker. The genes, tentatively named Sw5-a and Sw5-b, encode proteins of 1245 and 1246 amino acids, respectively, and are members of the coiled-coil, nucleotide-binding-ARC, leucine-rich repeat group of resistance gene candidates. Promoter and terminator regions of the genes are also highly homologous. Both genes significantly resemble the tomato nematode and aphid resistance gene Mi and, to a lesser extent, Pseudomonas syringae resistance gene Prf. Transformation of Nicotiana tabacum cv. SR1 plants revealed that the Sw5-b gene, but not the Sw5-a gene, is necessary and sufficient for conferring resistance against tomato spotted wilt virus.     

Genus delimitation,biogeography and diversification of Choristoneura Lederer (Lepidoptera: Tortricidae) based on molecular evidence

Widely known for pest species that include major modulators of temperate forests, the genus Choristoneura is part of the species‐rich tribe Archipini of leafroller moths (Tortricidae). Delimitation of the genus has remained unresolved because no phylogeny has included species endemic to Africa and studies have often omitted the type species of the genus. Further taxonomic confusion has been generated by the transfer of Archips occidentalis (Walsingham) to Choristoneura, creating a homonym with Choristoneura occidentalis Freeman, an important defoliator of North American forests. To define the limits of the genus, we reconstructed a phylogeny using DNA sequences for mitochondrial cytochrome oxidase subunit I and nuclear ribosomal 28S genes. Our ingroup included 23 Choristoneura species‐level taxa, complemented by a large sample of outgroups comprising 82 species of Archipini and other Tortricidae. We generated a time‐calibrated tree using fossil and secondary calibrations and we inferred biogeographic and diversification processes in Choristoneura. Our analysis recovered the genus as polyphyletic, with Archips occidentalis, Choristoneura simonyi and Choristoneura evanidana excluded from the main clade. Based on the recovered phylogenies and a redefinition, we restrict Choristoneura primarily to species with a northern hemisphere distribution. Our analysis supports A. occidentalis as the sister group of Cacoecimorpha pronubana, C. simonyi as the sister of ‘Xenotemna’ pallorana, and C. evanidana as the sister of Archips purpurana. A new combination is proposed: Archips evanidana comb.n. ; the availability of ‘Xenotemna’ as a valid name is discussed and A. occidentalis is considered as an orphaned name within the Archipini. We found support for a Holarctic origin of Choristoneura about 23 Ma, followed by early divergence in the Palearctic region. The main divergence occurred at 16 Ma, with one clade in the Nearctic and another in the Palearctic. Subsequent cladogenetic events were synchronous and related to herbivorous specialization, with each clade divided into coniferophagous and polyphagous lineages. Their specialization as conifer feeders temporally matched the expansion of boreal forest during the Miocene.     

Torsion Profiling of Proteins Using Magnetic Particles

We report a method to profile the torsional spring properties of proteins as a function of the angle of rotation. The torque is applied by superparamagnetic particles and has been calibrated while taking account of the magnetization dynamics of the particles. We record and compare the torsional profiles of single Protein G-Immunoglobulin G (IgG) and IgG-IgG complexes, sandwiched between a substrate and a superparamagnetic particle, for torques in the range between 0.5 × 10³ and 5 × 10³ pN·nm. Both molecular systems show torsional stiffening for increasing rotation angle, but the elastic and inelastic torsion stiffnesses are remarkably different. We interpret the results in terms of the structural properties of the molecules. The torsion profiling technique opens new dimensions for research on biomolecular characterization and for research on bio-nanomechanical structure-function relationships.     

The Anaerobic Fungus Neocallimastix sp. Strain L2: Growth and Production of (Hemi)Cellulolytic Enzymes on a Range of Carbohydrate Substrates

The anaerobic fungus Neocallimastix sp. strain L2, isolated from the feces of a llama, was tested for growth on a range of soluble and insoluble carbohydrate substrates. The fungus was able to ferment glucose, cellobiose, fructose, lactose, maltose, sucrose, soluble starch, inulin, filter paper cellulose, and Avicel. No growth was observed on arabinose, galactose, mannose, ribose, xylose, sorbitol, pectin, xylan, glycerol, citrate, soya, and wheat bran. The fermentation products after growth were hydrogen, formate, acetate, ethanol, and lactate. The fermentation pattern was dependent on the carbon source. In general, higher hydrogen production resulted in decreased formation of lactate and ethanol. Recovery of the fermented carbon in products at the end of growth ranged from 50% to 80%. (Hemi)cellulolytic enzyme activities were affected by the carbon source. Highest activities were found in filtrates from cultures grown on cellulose. Growing the fungus on inulin and lactose yielded the lowest cellulolytic activities. Highest specific activities for avicelase, endoglucanase, β-glucosidase, and xylanase were obtained with Avicel as the substrate for growth (0.29, 5.9, 0.57, and 13 IU · mg⁻¹ protein, respectively). Endoglucanase activity banding patterns after SDS-PAGE were very similar for all substrates. Minor differences indicated that enzyme activities may in part be the result of secretion of different sets of isoenzymes. Received: 10 July 1996 / Accepted: 22 July 1996     

Interrelations between sulfate-reducing and methane-producing bacteria in bottom deposits of a fresh-water lake. III. Experiments with 14C-labeled substrates

An ecological substrate relationship between sulfate-reducing and methane-producing bacteria in mud of Lake Vechten has been studied in experiments using ¹⁴C-labeled acetate and lactate as substrates. Fluoroacetate strongly inhibited the formation of ¹⁴CO₂ from [U-¹⁴C]-acetate and β-fluorolactate gave an inhibition of similar magnitude of the breakdown of [U-¹⁴C]-l-lactate to ¹⁴CO₂ thus confirming earlier results on the specific action of these inhibitors. The turnover-rate constant of l-lactate was 2.37 hr^-1 and the average l-lactate pool size was 12.2 μg per gram of wet mud, giving a turnover rate of 28.9 μg of lactate/gram of mud per hr. The turnover-rate constant of acetate was 0.35 hr^-1 and the average pool size was 5.7 μg per gram of wet mud, giving a rate of disappearance of 1.99 μg of acetate/gram of mud per hr. Estimations of the acetate turnover rate based upon the formation of ¹⁴CO₂ from [U-¹⁴C]-acetate or [1-¹⁴C]-acetate yielded figures of the same magnitude (range 0.45 to 1.74). These and other results suggest that only a portion of the lactate dissimilated is turned over through the acetate pool. The ratio of ¹⁴CO₂/¹⁴CH₄ produced from [U-¹⁴C]-acetate by mud was 1.32; indicating that 0.862 moles of CH₄ and 1.138 moles of CO₂ are formed per mole of acetate. From the rate of disappearance of acetate (0.027 μmoles/gram wet mud per hr) and the rate of methane production (0.034 μmoles/gram wet mud per hr), it may be concluded that acetate is an important precursor of methanogenesis in mud (approximately 70%). A substrate relationship between the two groups of bacteria is likely since ¹⁴CH₄ was formed from [U-¹⁴C]-l-lactate.