128 research outputs found
Successful transportation of wild stock of endangered "Thooli" (Labeo dussumieri) spawners without anaesthetics
Several problems are encountered during transportation of fishes from wild to
captivity. The note describes successful transportation of wild caught endangered
Labeo dussumieri spawners over distances below 100 km without anesthesia or
sophisticated transporting devices which is of immense help in the gene banking
programme of endangered species
Ecosystem Responses in the Distribution of Black Clam (Villorita cyprinoides) Beds in Vembanad Estuary during Environmental Changes Using GIS and RS
The biomass and distribution of black clam (Villorita cyprinoides) in Vembanad,
a tropical estuary located along the southwest coast of India varied significantly.
Sampling was done in freshwater-dominated zone in the south
(distal) and brackish water zone in the north (proximal), during pre and post
monsoon seasons. Clam biomass was estimated from samples, collected from
different stations during the study period. Water transparency and temperature
were measured at the sample sites. Water samples were collected and
analysed for salinity, dissolved oxygen (DO), pH and hardness. There was a
significant difference in the clam biomass during the two seasons in the distal
zone, and those collected from the distal and proximal zones during premonsoon
season. The data were further analysed to determine the factors affecting
the clam biomass distribution in the two zones and seasons. Factor
analyses, comparing the distal zone during two seasons and zonal variations
were similar to earlier observations. Step wise regression analyses found that
dissolved oxygen (adjusted R2 = 0.3) is the only variable affecting clam survival
during pre-monsoon period in the distal and proximal zones. A geographic
map of the region obtained from the Indian satellite sensor LISS
(Linear Image Self Scanner) was used along with in situ data to map the results
using inverse distance weightage model
Low Genetic Differentiation in the Populations of the Malabar Carp Labeo dussumieri as revealed by Allozymes, Microsatellites and RAPD
The population structure of Labeo dussumieri, an endangered and endemic cyprinid from
three riverine locations in the Western Ghats, India was investigated using allozyme, microsatellite
and RAPD markers. L. dussumieri samples were obtained from Meenachil, Manimala and Pamba
River basins, Kerala. Fourteen (46.7%) out of 30 allozyme loci, seven microsatellite loci and 12
RAPD Operon decamers gave polymorphic pattern. Six allozyme loci (AAT-2*, EST-4*, GLDH*,
GPI-2*, G6PDH* and LDH-2*) and three microsatellite loci (LdussG1, MFW19 and Bgon22)
exhibited consistent significant deviation from Hardy-Weinberg Equilibrium expectations in
different populations after probability level (P<0.05) was adjusted for sequential Bonferroni
correction. All the three marker types demonstrated concordant results and various estimates
revealed genetic variability within the subpopulations but surprisingly low level (= 0.0034 to
0.0081) of genetic differentiation among L. dussumieri from different river samples. AMOVA
analysis also indicated low differentiation among subpopulations. No evidence for a recent genetic
bottleneck was observed in L. dussumieri populations based on allozyme and microsatellite data
set analysis. Meenachil, Manimala and Pamba Rivers open in to the southern end of Vembanad
Lake in Kerala and are connected to each other in the lower reaches through an extensive network
of natural canals. Common ancestry in the prehistoric period; and possible mixing of fish
populations resulting in high gene flow across the rivers through the lake and interconnecting
canals could have been responsible for the lack of significant allelic heterogeneity among the
L. dussumieri populations. The stocks from the three rivers do not require different management
strategies and for propagation assisted river ranching programme of this species, large effective
breeding population can be developed by mixing individuals from three river
Breeding of endemic catfish, Horabagrus brachysoma in captive conditions
Asian seabass or barramundi (Lates calcarifer) is an important food fish with commercial
value and a wide geographic distribution. Though some reports based on molecular and/or
morphological data exist, a comprehensive effort to establish species identity across its
range is lacking. In order to address this issue and especially to ascertain whether the
wide-spread distribution has resulted in bifurcation of the species, we collected Asian
seabass samples from various locations representing the Western and Eastern Coastline
of India, Andaman and Nicobar Islands, Bangladesh and Australia. Samples from Malaysia,
Indonesia, Thailand and Singapore were collected as part of a previous study. DNA
sequence variations, including cytochrome c oxidase subunit 1 (COI), 16S rDNA and the
highly variable D-loop (or control region), were examined to establish species delineation.
Data from all the sequences analyzed concordantly point to the existence of at least two
distinct species—one representing the Indian subcontinent plus Myanmar, and a second,
representing Southeast Asia (Singapore, Malaysia, Thailand and Indonesia) plus Northern
Australia. These data are useful for conservation ecology, aquaculture management,
for establishing the extent of genetic diversity in the Asian seabass and implementing
selective breeding programs for members of this species complex
Length-weight relationship and condition factor of Dawkinsia filamentosa (Valenciennes, 1844) in different aquatic habitats
The growth rate of a species in any aquatic environment is an indicator of
the water quality of the system. In the current study, the Length-weight
relationship (LWR) and the condition factor of Dawkinsia filamentosa from
various aquatic ecosystems especially lotic, lentic and brackish lentic
systems were compared. It was observed that growth rate of the fish was
more in brackish lentic systems. The study showed that already reported
growth rate (b) of the species in brackish lentic systems is around 3.273
indicating proximity towards the isometric growth pattern as compared to
the growth rate in reservoirs (2.3184) and that in lentic systems
(3.116) obtained from present study. Similar studies supplemented with
environmental variables can be used to study the health status of the
ecosystem. The best system suitable for the adaptive growth of the
species can be ascertained only after a holistic approach involving
environmental variables
Genetic identification and phylogenetic relationships of Indian clariids based on mitochondrial COI sequences
Mitochondrial cytochrome C Oxidase I (COI) sequence variation among the clariid fishes of India
(Clarias magur, C. dussumieri and C. gariepinus) and their relationship with other representative
clariids was studied in this work. Three species were sampled and together with 23 COI sequences
from GenBank were used to reconstruct phylogenetic relationships in the family Clariidae. The
study revealed two clades: one consisting of the African species with C. dussumieri, and the other
of Asian species suggesting the prevalence of intra-continental diversification of catfishes. This
study further revealed that the genus Clarias is monophyletic. For the COI gene, the interspecies
genetic divergence ranged from 0.056 to 0.182. The mean genetic difference between C.
dussumieri and other selected African species in this study is 12.1%. It was also observed that the
morphological similarity of C. dussumieri and C. magur was not replicated in the genetic level.
Clarias dussumieri was more close to African catfish C. gariepinus thus indicating the utility of COI
phylogeny to identify the well-known African-Asian relationships within catfishes. The results also
showed that C. magur and C. batrachus are genetically distinct from each other
Mammalian Sperm Head Formation Involves Different Polarization of Two Novel LINC Complexes
Background: LINC complexes are nuclear envelope bridging protein structures formed by interaction of SUN and KASH proteins. They physically connect the nucleus with the peripheral cytoskeleton and are critically involved in a variety of dynamic processes, such as nuclear anchorage, movement and positioning and meiotic chromosome dynamics. Moreover, they are shown to be essential for maintaining nuclear shape. Findings: Based on detailed expression analysis and biochemical approaches, we show here that during mouse sperm development, a terminal cell differentiation process characterized by profound morphogenic restructuring, two novel distinctive LINC complexes are established. They consist either of spermiogenesis-specific Sun3 and Nesprin1 or Sun1g, a novel non-nuclear Sun1 isoform, and Nesprin3. We could find that these two LINC complexes specifically polarize to opposite spermatid poles likely linking to sperm-specific cytoskeletal structures. Although, as shown in co-transfection/ immunoprecipitation experiments, SUN proteins appear to arbitrarily interact with various KASH partners, our study demonstrates that they actually are able to confine their binding to form distinct LINC complexes. Conclusions: Formation of the mammalian sperm head involves assembly and different polarization of two novel spermiogenesis-specific LINC complexes. Together, our findings suggest that theses LINC complexes connect the differentiating spermatid nucleus to surrounding cytoskeletal structures to enable its well-directed shaping and elongation
LHC Magnet Tests: Operational Techniques and Empowerment for Successful Completion
The LHC magnet tests operation team developed various innovative techniques, particularly since early 2004, to complete the superconductor magnet tests by Feb. 2007. Overall and cryogenic priority handling, rapid on-bench thermal cycling, rule-based goodness evaluation on round-the-clock basis, multiple, mashed web systems are some of these techniques applied with rigour for successful tests completion in time. This paper highlights these operation empowerment tools which had a pivotal role for success. A priority handling method was put in place to enable maximum throughput from twelve test benches, having many different constraints. For the cryogenics infrastructure, it implied judicious allocation of limited resources to the benches. Rapid On-Bench Thermal Cycle was a key strategy to accelerate magnets tests throughput, saving time and simplifying logistics. First level magnet appraisal was developed for 24 hr decision making so as to prepare a magnet further for LHC or keep it on standby. Web based systems (Tests Management and E-Traveller) were other essential ideas to track & coordinate various stages of tests handled by different teams
Subcellular Localization of SUN2 Is Regulated by Lamin A and Rab5
SUN2 is an inner nuclear membrane protein with a conserved Sad1/UNC-84 homology SUN-domain at the C-terminus. Intriguingly, SUN2 has also been reported to interact with Rab5, which localizes in early endosomes. To clarify the dual subcellular localization of SUN2, we investigated its localization in lamin A/C deficient cells rescued with lamin A or lamin C isoform, and in HeLa cells transfected with Rab5 or its mutants. We found that expression of lamin A but not lamin C partly restored the nuclear envelope localization of SUN2. SUN2 was redistributed to endosomes upon overexpression of Rab5, but remained on the nuclear envelope when the SUN domain was deleted. To explore the physiological function of SUN2 in vesicle trafficking and endocytosis, we demonstrated the colocalization of endogenous SUN2 and Rab5. Moreover, overexpression of SUN2 stimulated the uptake of transferrin while suppression of SUN2 expression attenuated the process. These findings support a role of SUN2 in endocytosis
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