Cofactor Regeneration in Biocatalysis in Organic Media

Methods used for the regeneration of cofactors in organic media are reviewed. Substratedriven regeneration methods include the use of a second substrate of the same enzyme and the use of a second enzyme and its substrate. The use of mediators in oxidoreductions is described and examples of photochemical and electrochemical regeneration methods are presented. General problems and possibilities of cofactor regeneration in organic media are discussed.     

Childbearing in crisis: war, migration and fertility in Angola

This study examines the short- and long-term effects of war-induced and war-unrelated migration on fertility outcomes using data from two peri-urban municipalities of Greater Luanda in Angola. In the short term, results from multi-level discrete-time logistic regression models indicate that net of other factors, war-unrelated migration is associated with a lower probability of birth than war-induced migration in a given year. Similar results are obtained when the effects of migration are lagged by a year. At the same time, the effects of war-triggered migration do not differ significantly from those of not migrating in a given year but are statistically significant when the effects of migration are lagged by a year. In the long term, the effects of migration experience on cumulative fertility are negligible and not statistically significant net of demographic and socioeconomic variables. Interpretations of the results are offered in the context of Angola and their broader implications are reflected on.     

Dogs and Cats in Animal Shelters in Japan

ABSTRACT

Although there are proportionately fewer pet owners in Japan than in the United States, the keeping of indigenous Japanese dog breeds, along with those common in Europe and North America, is long-established. Japan has a centralized governmental network of animal shelters, which permits accurate record-keeping of the numbers of dogs and cats admitted, reclaimed, and euthanized. Although in the United States an accurate census is not simple to accomplish because a variety of humane societies and animal control agencies admit homeless dogs and cats, some cultural comparisons are possible.

Despite recent increases in petkeeping in Japan, the numbers of dogs admitted to shelters have decreased from 345,136 dogs in 1984 to 243, 753 dogs in 1994. The numbers euthanized show similar declines, from 331,442 in 1984 to 219,831 in 1994. In the city of Tokyo, kittens account for the majority of the animals admitted: 34,745 kittens (55%) of a total of 62,803 dogs and cats in 1980; 12,805 kittens (61%) of a total of 21,075 in 1993. Cats usually are brought in after being found on the street and are not reclaimed by their owners; virtually all are euthanized. Most dogs, 61%, are caught as strays by shelter personnel. Among those admitted to Tokyo shelters, 41% are reclaimed or returned to the owner, 7% are adopted by new owners, and 52% are euthanized.

Spaying and neutering of dogs and cats are not wide spread practices in Japan. There are few private shelters; the government provides no tax incentives for charitable contributions to such organizations. While American shelters invariably offer animals for adoption, most of Japan's governmental shelters do not. However, this is gradually changing.     

The Formation of Pollen Dimorphism in Paris axialis in Vivo

It is obsreved that the dimorphic populations of pollen are producedin Paris axialis H. Li In vivo. The normal pollen grains and abnormal pollen grainsare 77.1% and 22.9% respectively; more than 70% of abnormal pollen grains conformto the equal nucleus type. The abnormal pollen grains show no delayed development,and thay are stained as dark as the normal ones. During the first mitotic division of microspore, most of the spindles are anticlinal(perpendicular to the intine), the cytokinesis is generally asymmetric, and a completewall is formed. However, a few mitotic spindles of mitotic microspores are periclinal,and the cytokinesis are symmetric. Sometimes a partial wall is observed between twodaughter nuclei, which are produced by the abnormal pollen grains. We believe thatthese phenomena are related to differentiation of the dimorphic pollen.     

Paternity in horseshoe crabs when spawning in multiple-male groups

Unpaired or satellite male horseshoe crabs, Limulus polyphemus, are attracted to and often form a group around a pair (a female with an attached male) that is nesting in the high intertidal zone. These males are engaged in sperm competition. We observed nesting pairs and their associated satellites in the wild, collected and reared their eggs and used genetic markers to examine paternity. We found that the unpaired, satellite males are highly successful at fertilizing eggs; two satellites can leave the attached male with few fertilizations. Two satellites together are each as successful as one spawning with a pair. A satellite's location around the female greatly affects his success, and males compete for access to a position over the dorsal canal between the prosoma and opisthosoma of the female and under the front margin of the paired male where they are most likely to fertilize eggs. Although eggs and sperm retain their viability for some time after spawning, nearly all eggs are fertilized by the satellites that are around the nesting pair at the time of egg laying and by the attached male. A number of factors including beach current, female size and male behaviour affect the outcome of sperm competition in this externally fertilizing species. Copyright 2000 The Association for the Study of Animal Behaviour.     

细菌群体感应LuxR solos蛋白研究进展

N-酰基高丝氨酸内酯(N-acyl-L-homoserine lactones,AHLs)信号分子介导的群体感应(quorum sensing,QS)是一种普遍的革兰氏阴性细菌信息交流方式。AHL-QS系统包括Lux I型AHLs合成酶和LuxR型受体蛋白。然而,部分革兰氏阴性菌缺失1个或多个LuxI型AHLs合成酶,仅有未配对的LuxR型受体蛋白,该LuxR型受体蛋白称为LuxR solo或Orphan蛋白。LuxR solos蛋白在细菌窃听、种间和种内的信号交流中起重要作用,为群体感应研究领域的热点。本文主要综述细菌LuxR solos蛋白的发现、基本概念、蛋白结构及类型,阐述感应AHLs和非AHLs信号分子的重要LuxR solos蛋白及功能,并对群体感应LuxR solos蛋白的研究前景和意义进行了展望。     

Recent developments in membrane-based separations in biotechnology processes: review

Membrane-based separations are the most ubiquitous unit operations in biotech processes. There are several key reasons for this. First, they can be used with a large variety of applications including clarification, concentration, buffer exchange, purification, and sterilization. Second, they are available in a variety of formats, such as depth filtration, ultrafiltration, diafiltration, nanofiltration, reverse osmosis, and microfiltration. Third, they are simple to operate and are generally robust toward normal variations in feed material and operating parameters. Fourth, membrane-based separations typically require lower capital cost when compared to other processing options. As a result of these advantages, a typical biotech process has anywhere from 10 to 20 membrane-based separation steps. In this article we review the major developments that have occurred on this topic with a focus on developments in the last 5 years.     

Trinucleotide repeats are clustered in regulatory genes in Saccharomyces cerevisiae

The genome of Saccharomyces cerevisiae contains numerous unstable microsatellite sequences. Mononucleotide and dinucleotide repeats are rarely found in ORFs, and when present in an ORF are frequently located in an intron or at the C terminus of the protein, suggesting that their instability is deleterious to gene function. DNA trinucleotide repeats (TNRs) are found at a higher-than-expected frequency within ORFs, and the amino acids encoded by the TNRs represent a biased set. TNRs are rarely conserved between genes with related sequences, suggesting high instability or a recent origin. The genes in which TNRs are most frequently found are related to cellular regulation. The protein structural database is notably lacking in proteins containing amino acid tracts, suggesting that they are not located in structured regions of a protein but are rather located between domains. This conclusion is consistent with the location of amino acid tracts in two protein families. The preferred location of TNRs within the ORFs of genes related to cellular regulation together with their instability suggest that TNRs could have an important role in speciation. Specifically, TNRs could serve as hot spots for recombination leading to domain swapping, or mutation of TNRs could allow rapid evolution of new domains of protein structure.     

Indian science in transition

India is a country in transition, and so is its science. Scientific institutions, researchers, regulatory agencies, and government policies are in a state of flux as changes are instigated to overcome the bureaucracy and inertia that are characteristic of a populous developing nation.     

Improvements in optical methods for measuring rapid changes in membrane potential

Summary In an effort to increase the utility of optical methods for measuring membrane potential in excitable cells, an additional 369 dyes were tested on giant axons from the squid. Several promising dyes with relatively large absorption and fluorescence signals are described. In addition, a simple modification of the apparatus led to a sixfold increase in the size of dye-related birefringence signals. In preparations with a suitable geometry, these signals are as large as absorption signals but photodynamic damage and bleaching are eliminated when wavelengths longer than the absorption band are used.     

Rest in poultry

Resting behaviour as well as other maintenance behaviours were studied in a group of Jungle Fowl (10 ♀♀, 1 ♂) and in a group of a medium hybrid commercial laying strain (9 ♀♀, 1 ♂). Observations were carried out under spacious and varied housing conditions. Both groups were observed for seven 24-h periods. Sleeping and dozing are defined and described and 24-h patterns of rest and other maintenance behaviours are shown. Results and differences between groups are discussed.     

Sex differences in energy expenditure in non-human primates

Female mammals bear the energetic costs of gestation and lactation. Therefore, it is often assumed that the overall energetic costs are greater for females than they are for males. However, the energetic costs to males of intrasex competition may also be considerable, particularly if males maintain a much larger body size than females. Using data from 19 non-human primates, this paper examines the relationship between male and female energetic costs both in the short term (daily energy expenditure) and the long term (the energetic cost of producing a single offspring). It is shown that the major determinant of sex differences in energetic costs is body size dimorphism. In the long term, the energetic costs are often greater for females, but, when male body size exceeds female body size by 60% or more, male energetic costs are greater than those for females. That is, in highly sexually dimorphic species the energetic costs of gestation and lactation for the females are matched by the energetic costs to the males of maintaining a large body size.     

Pheromonal communication involved in courtship behavior in Diptera

Sex pheromones are known for many dipteran species and play an important role in courtship behavior, together with visual, tactile, acoustic and other factors. Pheromones for a number of dipterans have been recently identified. This survey covers a number of species in all the families that have been studied. The review discusses diverse courtship behaviors in Diptera, with a special focus on the sex pheromones involved. In the Nematocera suborder, pheromones are volatile components, which act at a distance. They are derived from short-chain alkanes with acetoxy groups (Cecidomyidae) or terpenes (Psychodidae). In the Cyclorrhapha, pheromones may be volatile, derived from alkanes (Tephritidae) or terpenes (Agromyzidae), or non-volatile, unsaturated or methyl-branched hydrocarbons, which act by contact (the other subgenera). The behavioral roles and regulation of these pheromones are described, and their importance in species recognition is discussed.     

Subcellular particles involved in the translocation of proteins in rat brain

Protein translocation systems which are inhibited by vinblastine, colchicine, and low calcium concentrations have been found in the cells of the brain slice. The early steps in the translocation pathways of newly synthesized protein have been studied by use of a double-label experiment in conjunction with subcellular fractionation. Certain subcellular particles have been positioned on the pathways with reference to vinblastine-sensitive translocation steps. There appears to be many subcellular organelles that are located downstream from a vinblastine-sensitive translocation step and which receive significant quantities of translocated protein within an hour of its synthesis. Some of these organelles co-enrich with the enzyme marker 5'-AMPase. Myelinated axons, Golgi derived vesicles, and smooth and rough endoplasmic reticulum all are enriched in fractions which contain a net vinblastine-sensitive importation of protein. The major particles, which lie upstream from a vinblastine-sensitive translocation step and are net exporters of protein on this system, are found in a brain capillary fraction. It is suggested that the most likely exporter present in these capillaries are the end feet of astrocyte glial cells.     

Liver and pancreas transplantation in Europe--and in Hungary.

Liver transplantation (LT) is the sole treatment modality of most of diffuse liver diseases. Simultaneous-pancreas-kidney (SPK) transplantation is also a life saving operation for IDDM patients. Both procedures are established treatment options in the European Community (EC) and in the US. These procedures are performed in a significantly smaller number in Hungary. Having a larger demand for LT than the supply of cadaver donors alternative solutions are sought to increase the number of transplantable livers. In Hungary partly the shortage of donors and the shortage of recipients are the factors rendering the number of LTs and SPKs low. These factors can be changed by better organisation and good survival data that make the two procedures accepted by the community of physicians.     

Primary sleep in vertebrates and its role in the genesis of hypobiosis in poikilotherms and hibernation in mammals

New data are presented on the homology between winter hibernation and hypobiosis in poikilotherms, as well as one of the resting forms of the primary sleep in vertebrates. Different stages of formation of a cycle "awakefulness-sleep" in evolution of vertebrates are discussed. On the basis of universal behavioural, somato-vegetative, neurophysiological, neurochemical correlates of resting forms, hypobiosis and winter hibernation, a discussion is made of the problem of genetic fixation in the genotype and phenotype of heterothermic mammals (hibernating ones) of those characters which are typical of the sleep in homoiothermic and poikilothermic vertebrates.     

Disruption of autophagy results in constitutive oxidative stress in Arabidopsis

Plant cells frequently encounter oxidative stress, leading to oxidative damage and inactivation of proteins. We have recently demonstrated that oxidative stress induces autophagy in Arabidopsis seedlings in an AtATG18a-dependent manner and that RNAi-AtATG18a transgenic lines, which are defective in autophagosome formation, are hypersensitive to reactive oxygen species. Analysis of protein oxidation indicated that oxidized proteins are degraded in the vacuole after uptake by autophagy, and this degradation is impaired in RNAi-AtATG18a lines. Our results also suggest that in the absence of a functional autophagy pathway, plants are under increased oxidative stress, even under normal growth conditions.