Distribution and conservation status of primates in Bioko island,Equatorial Guinea

Ten species of non-human primates are indigenous to Bioko; half of these are endangered and between five and eight are endemic subspecies. Recent data on their status and distribution have been lacking. In 1986, a ten-week survey of the island was carried out to determine the distribution and status of the primates and the natural vegetation, and to evaluate the effects of man on them. This paper presents the results of that survey, gives an update of conservation achievements since 1986, and highlights current concerns. Between 1974 and 1986 it is probable that numbers of all Bioko primates rose as a result of an increase in habitat and of reduced hunting. At the time of the survey there was considerably more natural, undisturbed, vegetation remaining in Bioko tran expected. Much of this vegetation occurs within two large blocks that are of outstanding importance to the conservation of species in tropical Africa, particularly of plants and primates.     

Endophytic fungi alter foraging and dispersal by desert seed-harvesting ants

Endophytic fungi are thought to interact mutualistically with host plants by producing alkaloid metabolites that deter herbivory. Since such fungi are transmitted via seed in some grasses, the presence of endophytes may also protect plants from seed predators. We conducted seed choice experiments for two dominant seed harvesting ants, Pogonomyrmex rugosus in the Sonoran desert and Pogonomyrmex occidentalis at a higher elevation, riparian zone in Arizona, USA. Non-infected fescue (Festuca arundinacea) seeds and seeds infected with the endophytic fungus, Acremonium coenophialum, were presented to ant colonies in three different populations. Infected seeds were harvested less frequently than non-infected seed for the two populations of Pogonomyrmex rugosus but not for the population of Pogonomyrmex occidentalis. We also a conducted seed dispersal experiment for one population of Pogonomyrmex rugosus. Of the seeds that were harvested, most of the colonies discarded more infected seeds into refuse piles than expected by chance. Seeds discarded into refuse piles have greater germination success than surrounding areas. The most important interaction of endophytes and grasses may be deterrence of seed predation and enhancing the probability of germinating in favorable sites, since these processes directly increase plant fitness.     

Effects of fire on water and salinity relations of riparian woody taxa

Water and salinity relations were evaluated in recovering burned individuals of the dominant woody taxa from low-elevation riparian plant communities of the southwestern U.S. Soil elemental analyses indicated that concentrations of most nutrients increased following fire, contributing to a potential nutrient abundance but also elevated alluvium salinity. Boron, to which naturalized Tamarix ramosissima is tolerant, was also elevated in soils following fire. Lower moisture in the upper 30 cm of burned site soil profiles was attributed to shifts in evapotranspiration following fire. Higher leaf stomatal conductance occurred in all taxa on burned sites. This is apparently due to higher photosynthetic photon flux density at the midcanopy level and may be partially mitigated by reduced unit growth in resprouting burned individuals. Predawn water potentials varied little among sites, as was expected for plants exhibiting largely phreatophytic water uptake. Midday water potentials in recovering Salix gooddingii growing in the Colorado River floodplain reached levels which are considered stressful. Decreased hydraulic efficiency was also indicated for this species by examining transpiration-water potential regressions. Recovering, burned Tamarix and Tessaria sericea had enriched leaf tissue ¹³C relative to unburned controls. Higher water use efficiency following fire in these taxa may be attributed to halophytic adaptations, and to elevated foliar nitrogen in Tessaria. Consequently, mechanisms are proposed which would facilitate increased community dominance of Tamarix and Tessaria in association with fire. The theory that whole ecosystem processes are altered by invading species may thus be extended to include those processes related to disturbance.     

Effect of agitation speed on the synthesis of Mucor miehei acid protease

Different experiments using Mucor miehei CBS 370.65 were carried out to study the effect of agitation speed on the production of the mold acid protease. The experiments were conducted in shake flasks at a fixed substrate concentration of 58 g l⁻¹ of total carbohydrates and at shaker speeds from 80 to 380 rev min⁻¹. Enzyme production was found to be directly proportional to the shaker speeds, with the highest concentration of enzyme of 1,400 Soxhlet Rennet units (SU) ml⁻¹ obtained at 380 rev min⁻¹. The yield of product to substrate at 380 rev min⁻¹ was determined to be 27,081.0 SU g⁻¹ substrate and the productivity of the process was 221 SU g⁻¹ h⁻¹. Enzyme production was partially growth associated, and glucose supported both cell growth and enzyme production. Product formation and cell concentration were directly related to the rate of substrate consumption. The rate of product formation decreased when product started to accumulate, suggesting that the process was affected by feedback repression.     

Effects of 60 Hz electric and magnetic fields on maturation of the rat neopallium

This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham-exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF-EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA. RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF-EM fields caused minimal or no changes in somatic growth and cerebral development of the rat. © 1993 Wiley-Liss, Inc.     

Impact of Chlorine and Heat on the Survival of Hartmannella vermiformis and Subsequent Growth of Legionella pneumophila

Hartmannella vermiformis, a common amoebal inhabitant of potable-water systems, supports intracellular multiplication of Legionella pneumophila and is probably important in the transportation and amplification of legionellae within these systems. To provide a practical guide for decontamination of potable-water systems, we assessed the chlorine and heat resistance of H. vermiformis. H. vermiformis cysts and trophozoites were treated independently with chlorine at concentrations of 2.0 to 10.0 ppm for 30 min and then cocultured with L. pneumophila. Both cysts and trophozoites were sensitive to concentrations between 2.0 and 4.0 ppm and above (trophozoites somewhat more so than cysts), and 10.0 ppm was lethal to both forms. Hartmannellae treated with chlorine up to a concentration of 4.0 ppm supported the growth of legionellae. To determine whether heat would be an effective addendum to chlorine treatment of amoebae, hartmannellae were subjected to temperatures of 55 and 60°C for 30 min and alternatively to 50°C followed by treatment with chlorine at a concentration of 2 ppm. Fewer than 0.05% of the amoebae survived treatment at 55°C, and there were no survivors at 60°C. Pretreatment at 50°C appeared to make hartmannella cysts more susceptible to chlorine but did not further reduce the concentration of trophozoites.     

Optimization of alkyl beta-D-galactopyranoside synthesis from lactose using commercially available beta-galactosidases

Commercially available lactase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) enzymes produced from Kluyveromyces fragilis and Kluyveromyces lactis were accessed as catalysts for use in the production of beta-galactopyranosides of various alcohols using lactose as galactosyl donor. The yield of galactoside was enhanced by using the highest practical concentrations of both lactose and alcohol acceptor. The concentrations and thus yield, were limited by the solubility of the substrates. The increase in galactoside yield with increasing lactose concentration appeared to be specific to the lactose substrate and not due to water activity alterations, because addition of maltose to a fixed concentration of lactose had no effect. During the course of the reaction, the yield of galactoside peaked after around 70% to 80% of the lactose was consumed, due to hydrolysis of the product by the enzyme. A wide variety of compounds with primary or secondary hydroxyl groups could act as acceptors, the essential requirement being at least some water solubility. Addition of organic cosolvents had little effect on galactoside yield except when it increased the water solubility of sparingly soluble alcohols. Some galactosides were synthesized on a gram scale to determine practical product recoveries and improve purification methods for large-scale synthesis. Initial purification by hydrophobic chromatography (for galactosides of hydrophobic alcohols) or strong anion-exchange chromatography (for galactosides of hydrophilic alcohols) separated galactosides, galactobiosides, and higher oligomers from reducing sugars. A facile separation of the galactoside and galactobioside could then be effected by flash chromatography on silica gel. (c) 1993 John Wiley & Sons, Inc.     

Analysis of the Intermolecular Contacts within Sickle Hemoglobin Fibers: Effect of Site-Specific Substitutions, Fiber Pitch, and Double-Strand Disorder

An atomic model of the sickle hemoglobin (HbS) fiber was synthesized by combining the molecular coordinates of the fiber (obtained from electron microscopy) with atomic coordinates of the sickle hemoglobin double strand (obtained from X-ray crystallography). The model is stereochemically acceptable. The majority of polymerization-sensitive HbS mutants are located at fiber contact sites and the majority of the mutants that do not affect polymerization are not located at contact sites. The residues at intermolecular contacts in the fiber model are reported. We have searched the coordinate space in the vicinity of the EM reconstructions to find models with alternative sets of coordinates that satisfy the mutant data, contain 5-Å contacts between double strands, and are stereochemically acceptable. This involved a systematic examination over 297 different models. The alternative fiber models were generated with a range of fiber pitch, double-strand positions, and double-strand polarity. Models which had unacceptably close contacts between atoms, failed to satisfy the mutant data, or did not have 5-Å contacts between double strands were considered unacceptable. None of the acceptable alternative fiber models improved the agreement between the polymerization behavior of HbS mutants and their contact site location. However, several models could account for the polymerization data equally well. Residue locations for single-site HbS mutations that could discriminate between alternative fiber models are proposed. The twist of HbS fibers varies in an apparent random manner with an average rotation of 7.8 ± 2.5° per molecule and a maximum rotation of 16° per molecule. The number of interdouble-strand contacts as a function of fiber twist shows a broad maximum around 9° and may account for the observed range of fiber pitch. This study shows that the upper limit on the fiber twist could result from a loss of axial contacts and repulsive van der Waals interactions between residues involved in interstrand contacts. The loss of axial contacts limits the radial growth of the fiber. In the appendix we analyze the methodology used by I. Cretegny and S. J. Edelstein [(1993) J. Mol. Biol. 230, 733-738] to build a model of the fiber. Our examination reveals shortcomings in the methodology of Cretegny and Edelstein. One result of these shortcomings is that the model synthesized by Cretegny and Edelstein is not stereochemically acceptable because it gives rise to a large number of excessively close (less than 1.4 Å) atom-atom contacts, suggesting interpenetration of the molecular envelopes.     

The 141-year period for Dr. Beal's seed viability experiment: A hybrid surprise

Premise

In 1879, Dr. William Beal buried 20 glass bottles filled with seeds and sand at a single site at Michigan State University. The goal of the experiment was to understand seed longevity in the soil, a topic of general importance in ecology, restoration, conservation, and agriculture, by periodically assaying germinability of these seeds over 100 years. The interval between germination assays has been extended and the experiment will now end after 221 years, in 2100.

Methods

We dug up the 16th bottle in April 2021 and attempted to germinate the 141-year-old seeds it contained. We grew germinants to maturity and identified these to species by vegetative and reproductive phenotypes. For the first time in the history of this experiment, genomic DNA was sequenced to confirm species identities.

Results

Twenty seeds germinated over the 244-day assay. Eight germinated in the first 11 days. All 20 belonged to the Verbascum genus: Nineteen were V. blattaria according to phenotype and ITS2 genotype; and one had a hybrid V. blattaria × V. thapsus phenotype and ITS2 genotype. In total, 20/50 (40%) of the original Verbascum seeds in the bottle germinated in year 141.

Conclusions

While most species in the Beal experiment lost all seed viability in the first 60 years, a high percentage of Verbascum seeds can still germinate after 141 years in the soil. Long-term experiments such as this one are rare and invaluable for studying seed viability in natural soil conditions.     

TGN38/41: a molecule on the move

TGN38/41 is a heterodimeric integral membrane protein that cycles between the trans Golgi network and the cell surface. A tyrosine-containing tetrapeptide motif within its cytoplasmic tail is necessary and sufficient for determining its steady-state location in the TGN. Recent results have shown that TGN38/41 plays an essential role in the formation of exocytic vesicles at the TGN by serving as a receptor for complexes of a cytoplasmic protein known as p62, and one of four small GTP-binding proteins, including rab6. For budding to occur, this complex must bind to the cytoplasmic domain of TGN38/41. We propose here that TGN38/41 may couple the segregation of secretory proteins to the budding of exocytic vesicles at the TGN.