Mutant PCNA alleles are associated with cdc phenotypes and sensitivity to DNA damage in fission yeast

Twenty-eight site-directed mutations were introduced into the fission yeast gene (pcn1 ⁺) that encodes proliferating cell nuclear antigen (PCNA) and their in vivo effects analyzed in a strain with a null pcn1 background. Mutants defective in enhancing processivity of DNA polymerase δ have previously been identified. In this study, we assessed all of the mutants for their sensitivities to temperature, hydroxyurea, UV irradiation and methyl methanesulfonate (MMS), and specific mutants were also tested for sensitivity to γ irradiation. One cold-sensitive allele, pcn1-3, was characterized in detail. This mutant had a recessive cold-sensitive cdc phenotype and showed sensitivity to hydroxyurea, UV, and γ irradiation. At the non-permissive temperature pcn1-3 protein was able to form homotrimers in solution and showed increased stimulation of both synthetic activity and processivity of DNA polymerase δ relative to the wild-type Pcn1⁺ protein. Epistasis analyses indicated that pcn1-3 is defective in the repair pathway involving rad2 ⁺ but not defective in the classical nucleotide excision repair pathway involving rad13 ⁺ . Furthermore, pcn1-3 is either synthetically or conditionally lethal in null checkpoint rad backgrounds and displays a mitotic catastrophe phenotype in these backgrounds. A model for how pcn1-3 defects may affect DNA repair and replication is presented. Received: 5 July 1997 / Accepted: 10 October 1997     

Australian Anthropology,Ideology and Political Repression: The Cold War Experience of Frederick G. G. Rose

It is more than half a century since Frederick G. G. Rose (1915–1991) published his classic text, The classification of kin, age structure and marriage amongst the Groote Eylandt Aborigines: A study in method and a theory of kinship (1960) in the former German Democratic Republic. Although the fieldwork for his thesis had been carried out in Australia on Groote Eylandt in 1938 and 1941, a conservative academic establishment and the political climate of the Cold War postponed its publication until 1960. Why were Rose's fieldwork findings suppressed by the powerful gate-keeper of Australian anthropology, Professor Adolphus Peter Elkin (1891–1979)? Moreover, why was Rose later denied a government permit to revisit Groote Eylandt and Central Australia to further his research? This paper examines the early work of the communist anthropologist, Frederick Rose, within the broad context of Western post-war anthropological developments, an expanding capitalist economy and the political tensions of the Cold War era. As a communist and public servant from 1938 to 1954, Rose was forced, after the Petrov Royal Commission cast him under a cloud of suspicion, to seek institutional support for his academic career in the German Democratic Republic.     

Sievoides kocyigiti n. gen., n. sp., Mesoendothyra altineriana n. sp. and Kurnubia feleensis n. sp. from Kimmeridgian shallow water limestones intercalated with alkaline igneous rocks, Western Taurus, Turkey

In the framework of the palaeogeographical reconstruction of the Western Taurus during Jurassic, the study of northern and eastern boundary of the Taurids started. Detailed facies analysis evidenced the position of the Barla Dag ramp between two elevated areas: the southern rimmed shelf extension of the platform system and the northern neritic-beach-land plain. In the basal biostratigraphical and ecological characteristics of the Balcikhisar volcano-sedimentary sequence, correlated with the Fele outcrop, one genus and three new species of foraminifers have been found: Sievoides kocyigiti n. gen., n. sp. and Mesoendothyra altineriana n. sp. from neritic environment, and Kurnubia feleensis n. sp. from rimmed shelf lagoon. Both carbonate sedimentary deposits are intercalated with spilitic-basalt pillow lava flows. The age of the new three species is Kimmeridgian, controlled by some foraminifer golden hooks.     

Ecology,distribution mapping and conservation implications of four critically endangered endemic plants of Kashmir Himalaya

During the last few decades, human-driven activities have led to indiscriminate habitat destruction and exploitation of many plant species in Kashmir Himalaya. As a result, many species have become threatened and are struggling for survival. Of particular concern are the endemic and critically endangered species which have the highest risk of the extinction, hence warranting immediate conservation actions. Therefore the current study was carried out to understand the distribution, ecology and conservation implications of the four critically endangered endemic plants of Kashmir Himalaya. Habitat distribution modelling showed that the suitable potential areas for the species occurred from subalpine to alpine meadowlands with an elevational range of 1500–4600 m asl. The output of the MaxEnt model and field surveys have revealed that their highest potential distribution is in Panchari, Khrew, Ramnagar, Pahalgam, Gurez, Sonamarg, Gulmarg and Kishtwar forest ranges. Based on the field explorations and herbarium records, Saussurea costus (Falc.) Lipsch have 27 distribution areas, Gentiana kurroo Royle 18, Lilium polyphyllum D. Don 12 and Aconitum chasmanthum Stapf have 15. Precipitation of the driest month and annual mean temperature played an important role in the distribution of the studied species. The species started their lifecycle with the onset of the spring season, flowered in summer, fruit in autumn and senesce in the winter season. Under natural conditions, the number of days required for germination ranged from 180 to 210 where cold stratification played a pivotal role. Since last few decades, the populations of these species have been shrinking in their natural habitats due to over-exploitation for medicinal purposes and habitat destruction through amplified humanoid interferences like the expansion of agricultural land, road building, grazing and urbanization. Thus there is an urgent need to come up with positive strategies to save whatever is left and plan long term rescue measures not only to protect these species from extinction but also to reintroduce them along with framing the plans to supply sustained raw materials for medicine.     

Bestimmung der Verdaulichkeit der Rohnährstoffe,Basischen und Schwefelhaltigen Aminosäuren von Natürlich und Technisch Getrockneten Rotkleeblättern an Kolostomierten Legehennen

Domesticated animals all over the world are subjected to a wide variety of environmental conditions and challenges. Any deviation from “normal”; may result in adaptive behavior of which changes in feed intake or feed intake pattern is by far the most important. Adaptive behavior may further include influences on passage rate of feed residues through the digestive tract, resulting in changes in digestibility. Adaptive behavior may also result in changes in heat production, either to maintain body temperature constant, or as a result of an elevated body temperature.

Important environmental challenges are infectious diseases. Mild (sub‐clinical) infections usually result in reduced performance, without affecting feed intake or digestibility. Severe infections may disrupt the barriers between the internal metabolism and the respiratory and/or digestive tract, resulting in severe losses of energy and protein. This situation is notably apparent in severe infections with parasites of the gastrointestinal tract and may be associated with severe protein losses. Feeding high protein diets may partly alleviate the negative effects.

Contamination of air, water and feed may occasionally cause problems in farm animals. Such contamination may include pathogenic microbes, toxic secondary fungal metabolites and heavy metals. Negative effects associated with such contamination often show an impaired reproductive efficiency, but their influence on the utilization of energy and nutrients is not well documented.     

Respiratory changes due to extreme cold in the Arctic environment

Effects of acute exposure and acclimatisation to cold stress on respiratory functions were investigated in healthy tropical Indian men (n=10). Initial baseline recordings were carried out at Delhi and thereafter serially thrice at the arctic region and once on return to Delhi. For comparison the respiratory functions were also evaluated on Russian migrants (RM;n=7) and Russian natives (RN;n=6). The respiratory functions were evaluated using standard methodology on a Vitalograph: In Indians, there was an initial decrease in lung vital capacity (VC), forced vital capacity (FVC), forced expiratory volume 1st s (FEV1), peak expiratory flow rate (PEFR) and maximum voluntary ventilation (MVV) on acute exposure to cold stress, followed by gradual recovery during acclimatisation for 4 weeks and a further significant improvement after 9 weeks of stay at the arctic region. On return to India all the parameters reached near baseline values except for MVV which remained slightly elevated. RM and RN showed similar respiratory functions at the beginning of acute cold exposure at the arctic zone. RN showed an improvement after 10 weeks of stay whereas RM did not show much change. The respiratory responses during acute cold exposure are similar to those of initial altitude responses.     

Psychrotolerant bacteria isolated from the leaf apoplast of cold-adapted wild plants improve the cold resistance of bean (Phaseolus vulgaris L.) under low temperature

We have isolated psychrotolerant bacteria from the leaf apoplast of cold-adapted wild plants and aimed to investigate their effect on the cold resistance of bean (Phaseolus vulgaris L.). Based on the findings of 16S rRNA gene sequence analysis, 20 isolates belonging to 5 bacteria species (Pseudomonas fragi, P. chloropaphis, P. fluorescens, P. proteolytica and Brevibacterium frigoritolerans) were identified in the leaf apoplastic fluid of Draba nemorosa, Galanthus gracilis, Colchicum speciousum, Scilla siberica, Erodium cicutarium, respectively. We have determined that 6 of the 20 isolates have exhibited ACC (1-aminocyclopropane-1-carboxylate) deaminase activity and secreted different extracellular proteins under cold condition (+4 °C) compared to normal growth condition (28 °C). The six isolates were then inoculated independently of each other to the leaves of 10-day-old bean seedlings growing under normal conditions (25/22 °C, 16/8 h photoperiod), and the inoculated and uninoculated (control) seedlings were transferred to cold (9/5 °C, 16/8 h photoperiod) for 3 days. The bacterial inoculations have decreased freezing injury, ice nucleating activity and lipid peroxidation content in parallel with the decrease of reactive oxygen species level such as O₂^.- and H₂O₂ in the inoculated seedlings compared to the control. In addition, the inoculations of the isolates have stimulated the activity of apoplastic antioxidant enzymes including superoxide dismutase, catalase, peroxidase, and glutathione reductase. The results show that the inoculations improve the cold resistance of bean seedlings and the psychrotolerant bacterial isolates can be evaluated within the group of plant growth promoting bacteria (PGPB) which can increase tolerance of cold-sensitive crops.     

Influence of learning on range expansion and adaptation to novel habitats

Learning has been postulated to ‘drive’ evolution, but its influence on adaptive evolution in heterogeneous environments has not been formally examined. We used a spatially explicit individual‐based model to study the effect of learning on the expansion and adaptation of a species to a novel habitat. Fitness was mediated by a behavioural trait (resource preference), which in turn was determined by both the genotype and learning. Our findings indicate that learning substantially increases the range of parameters under which the species expands and adapts to the novel habitat, particularly if the two habitats are separated by a sharp ecotone (rather than a gradient). However, for a broad range of parameters, learning reduces the degree of genetically‐based local adaptation following the expansion and facilitates maintenance of genetic variation within local populations. Thus, in heterogeneous environments learning may facilitate evolutionary range expansions and maintenance of the potential of local populations to respond to subsequent environmental changes.     

Characterization of two copper/zinc superoxide dismutases (Cu/Zn-SODs) from the desert beetle Microdera punctipennis and their activities in protecting E. coli cells against cold

Superoxide dismutases (SODs) are crucial in scavenging reactive oxygen species (ROS); however, studies regarding SOD functions in insects under cold conditions are rare. In this paper, two novel Cu/Zn-SOD genes in the desert beetle Microdera punctipennis, an extracellular copper/zinc SOD (MpecCu/Zn-SOD) and an intracellular copper/zinc SOD (MpicCu/Zn-SOD), were identified and characterized. The results of quantitative real-time PCR showed that MpecCu/Zn-SOD expression was significantly up-regulated by 4 °C exposure for 0.5 h, but MpicCu/Zn-SOD was not. Superoxide anion radical (O₂•^-) content in beetles under 4 °C exposure for 0.5 h showed an initial sharp increase and fluctuated during the cold treatment period, which was consistent with the relative mRNA level of MpecCu/Zn-SOD. The total SOD activity in the beetle was negatively correlated to the O₂•^- content with a correlation coefficient of −0.437. An E. coli system was employed to study the function of each MpCu/Zn-SOD gene. The fusion proteins Trx-His-MpCu/Zn-SODs were over expressed in E. coli BL21 using pET32a vector, and identified by SDS-PAGE and Western blotting. The transformed bacteria BL21(pET32a-MpecCu/Zn-SOD) and BL21(pET32a-MpicCu/Zn-SOD) showed increased cold tolerance to −4 °C as well as increased SOD activity compared to the control BL21(pET32a). The relative conductivity and malondialdehyde content in the two MpCu/Zn-SODs transformed bacteria under −4 °C were significantly lower than the control BL21(pET32a). Furthermore, BL21(pET32a-MpecCu/Zn-SOD) had significantly higher SOD activity and cold tolerance than BL21(pET32a-MpicCu/Zn-SOD) under −4 °C treatment, and had lower conductivity than BL21(pET32a-MpicCu/Zn-SOD). In conclusion, low temperature led to the accumulation of O₂•^- in M. punctipennis, which stimulated the expression of extracellular MpCu/Zn-SOD gene and the increase of total SOD activity. E. coli overexpressing Trx-His-MpCu/Zn-SODs increased resistance to cold treatment-induced oxidative stress. Our findings will be helpful in further study of Cu/Zn-SOD genes in insect cold-tolerance.