Cold hardening treatment - a brief exposure to low temperatures - can protect certain insects against subsequent exposure to temperatures sufficiently low to cause damage or lethality. Microarray analysis to examine the changes in transcript abundance associated with cold hardening treatment (0 degrees C for 2 h followed by 30 min recovery at 25 degrees C) was undertaken in Drosophila melanogaster in order to gain insight into this phenomenon. Transcripts associated with 36 genes were identified, a subset of which appeared to be also differentially expressed after heat shock treatment. Quantitative RT-PCR was used to independently determine transcript abundance of a subset of these sequences. Taken together, these assays suggest that stress proteins, including Hsp23, Hsp26, Hsp83 and Frost as well as membrane-associated proteins may contribute to the cold hardening response.

To assess the functional significance of adenosine salvage in plants, the cDNAs and genes encoding two isoforms of adenosine kinase (ADK) were isolated from Arabidopsis. The ADK1-and ADK2-coding sequences are very similar, sharing 92% and 89% amino acid and nucleotide identity, respectively. Each cDNA was overexpressed in Escherichia coli, and the catalytic activity of each isoform was determined. Both ADKs had similar catalytic properties with a K m and V max /K m for adenosine of 0.3 to 0.5 m and 5.4 to 22 L min Ϫ1 mg Ϫ1 protein, respectively. The K m and V max /K m for the cytokinin riboside N 6 (isopentenyl) adenosine are 3 to 5 m and 0.021 to 0.14 L min Ϫ1 mg Ϫ1 protein, respectively, suggesting that adenosine is the preferred substrate for both ADK isoforms. In Arabidopsis plants, both ADK genes are expressed constitutively, with the highest steady-state mRNA levels being found in stem and root. ADK1 transcript levels were generally higher than those of ADK2. ADK enzyme activity reflected relative ADK protein levels seen in immunoblots for leaves, flowers, and stems but only poorly so for roots, siliques, and dry seeds. The catalytic properties, tissue accumulation, and expression levels of these ADKs suggest that they play a key metabolic role in the salvage synthesis of adenylates and methyl recycling in Arabidopsis. They may also contribute to cytokinin interconversion.

Abstract:Understanding household livelihood strategies is pivotal to minimize rural poverty in the least developed countries like Nepal. This study is an attempt to assess livelihood strategies pursued by rural households, investigate the most remunerative strategy, and identify the factors that influence a household's choice of better strategies in rural Nepal. Primary data collected in 453 households from three villages of central Nepal are analyzed quantitatively within a sustainable livelihood framework. This study categorized households into five main livelihood strategy groups. The results showed that the majority (61%) of the households diversified their income to non-farm sources. Livelihood diversification to business/enterprise strategies adopted by 16% of the households is the most remunerative strategy followed by commercial farming that includes 13% of the sample and are more relevant to poverty reduction. Land holding, education, agriculture and skill training, access to credit, and proximity to the road and market center are the major influencing factors on the adoption of higher returning livelihood strategies. Stimulating poor households to follow market-oriented farm and non-farm activities by improving access to education, vocational training, rural credit, and rural infrastructures is momentous for reducing poverty in the rural areas of central Nepal.