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[A1CR]

A member of the
http://en.wikipedia.org/wiki/Tetranychus_urticae family is
the two-spotted spider mite. The first paper below (1)
appears to
demonstrate that the two-spotted spider mite responds with
expression of the
stress heat shock cognate 70 (hsc70) with starvation, but
not heat shock,
and is not pdf-availed. The second paper below (2)
seemingly reports that
expression of heat shock constitutive 70 (Hsc70) protein
increases with
aging and that this effect of aging is lowered by CR via
intermittent
feeding.

1. Berthoud HR, Sutton GM, Townsend RL, Patterson LM, Zheng H.
Brainstem mechanisms integrating gut-derived satiety signals
and descending
forebrain information in the control of meal size.
Physiol Behav. 2006 Sep 21; [Epub ahead of print]
PMID: 16996546

We isolated a heat shock cognate 70 (hsc70) gene from
the two-spotted spider mite, Tetranychus urticae, a serious
agricultural pest. The hsc70 cDNA is 2275 bp and contains a
1962 bp open reading frame. The translated amino acid
sequence consists of 654 residues with a calculated
molecular mass of 71,275 Da and an isoelectronic point (pI)
of 5.52. It also contains the highly conserved functional
motifs of the Hsp70 family. A comparison of the deduced
amino acid sequence shows a high identity (81-84%) with
Hsp70s/Hsc70s of insects but the highest identity is with
mussel Hsc71 (86%). Northern blot hybridization indicates
that the hsc70 transcript level of female adults is higher
than that of male adults. We evaluated the response of hsc70
gene to stresses from temperature and starvation. The level
of hsc70 mRNA was not significantly changed by heat and cold
shocks nor by recovery after the shocks. However, the hsc70
mRNA level was decreased by food restriction of female
mites. Analysis of nucleotide and deduced amino acid
sequences of hsc70 gene from T. urticae suggests that it is
a member of heat shock cognate 70 gene in the highly
conserved Hsp70 family but that its expression is influenced
by food restriction rather than thermal stress. This is the
first molecular analysis of a heat shock protein gene in an
acarid.

2. Unno K, Asakura H, Shibuya Y, Kaiho M, Okada S, Oku N.
Increase in basal level of Hsp70, consisting chiefly of
constitutively
expressed Hsp70 (Hsc70) in aged rat brain.
J Gerontol A Biol Sci Med Sci. 2000 Jul;55(7):B329-35.

PMID: 10898246

Abstract:

Alteration of proteins in the function and higher
structure has been observed in aged organisms. Stress
proteins, which have a role to protect proteins from
denaturation, may respond to the protein denaturation with
aging. We found that the basal level of Hsp70, consisting
chiefly of constitutively expressed Hsp70 (Hsc70), in
24-month-old Wistar rats was significantly higher in some
parts of the brain than that in 6-month-old rats. On the
other hand, the basal level of Hsp70 was significantly lower
in 24-month-old rats after restricted feeding, which is
known to suppress aging, than those fed the diet ad libitum.
In the pons, medulla, striatum, and thalamus of 24-month-old
rat brain, the level of Hsp70 increased and the denaturation
of the cytosol proteins was suppressed. These results
suggest that the expression of Hsp70, mostly Hsc70,
increases with aging and may have a role to suppress protein
denaturation.

Excerpts:

... In the present study, we found that the basal
levels of Hsp70 in
some parts of the rat brain, such as pons, striatum, and
thalamus, were
higher in aged than young animals. ... as caloric
restriction is known to
have a suppressive effect on aging and reduce oxidative
stresses ... We
found that the level of Hsp70 was decreased by dietary
restriction.
Additionally, the amount of the heat-instable protein
fraction was higher in
some parts of the brain of 24-month-old rats than those of
6-month-old rats.
However, the heat instability was suppressed in those parts
with an
increased level of Hsp70. In the aged rat brain, the
increased level of
Hsp70, mostly Hsc70, might have a role to protect proteins
from denaturing
stress.

... Rats aged 6 to 24 months old ... were fed a
certified commercial
pellet diet (MF; Oriental Yeast Co., Tokyo) ad libitum
(Normal). In the
dietary restriction (DR) experiment, two groups of
14-month-old rats (n=3),
which had been fed ad libitum previously, were fed MF every
other weekday
for 4 and 10 months, respectively; the dietary restriction
resulted in a
food intake of about half the normal. ...

... Increased expression of Hsp70 in the aged rat
brain. ... on 8 parts
of the brain (i.e., cerebellum, mesencephalon, cerebral
cortex, pons and
medulla, hippocampus, striatum, thalamus, and hypothalamus)
of 6- to
24-month-old rats (Fig. 3 a-h). The levels of Hsp70 ... were
significantly
higher in 24-month-old rats than in 6-month-old rats in the
pons and
medulla, striatum, and thalamus (Fig. 3 d, f, and g). In the
cerebral
cortex, hippocampus, and hypothalamus, the levels tended to
increase in
24-month-old rats (Fig. 3 c, e, and h). On the other hand,
the amounts of
Hsp70 cerebellum and mesencephalon were little increased
(Fig. 3 a and b).
In the liver, the level of Hsp70 did not increase with aging
and was
generally lower than that in the brain (Fig. 3 i).

... Hsp72 in the 24-month-old rats ... was very low in
these rat brains
(Fig. 2 and Fig. 4). The Hsp72 levels in the 6-month-old rat
brains were
similar to those in the 24-month-old rats (Fig. 2 b and d).
Hsc70 was
dominant and the level of Hsp72 was very low in these
unstressed animals
(i.e., the basal level of Hsp70 consisted mostly of Hsc70).
The increased
Hsp70 in the aged rat brain was thought to be of Hsc70. The
immunoblots
determined with anti-Hsc70, 1B5 and 13D3, were similar to
that with MAb
7.10, suggesting that the basal level of Hsp70 consisted
mostly of Hsc70
(data not shown).

... Effect of dietary restriction on Hsc70 in the rat
brain ... Two
groups of 14-month-old rats ... The body weights of 10-month
DR rats were
330-370 g and were about 80% of those of the same age-group
rats fed ad
libitum (420-460 g). In the 18-month-old rats restricted
from food for 4
months, the levels of Hsp70 were slightly lowered in the
striatum,
hippocampus, pons and medulla, but not in the other parts
(data not shown).
In the 24-month-old DR rats restricted from food for 10
months, the amounts
of Hsp70 were significantly lower in most brain parts
compared with those of
the same age-group rats fed ad libitum (Fig. 5). The basal
Hsp70 levels in
these parts of the 24-month-old DR rats were similar to
those in the
6-month-old rats shown in Fig. 3.

... Heat-stability of cytosol proteins of the aged rat
brain. ... in
the cerebellum, mesencephalon, cerebral cortex, hippocampus,
striatum, pons
and medulla, and thalamus of the 6- and 24-month-old rats.
The increase in
basal Hsp70 level was little in the cerebellum and
mesencephalon, but it was
significant in the pons + medulla, striatum, and thalamus.
In cerebral
cortex and hippocampus, the levels tended to increase. The
heat stability at
42°C of the proteins from the 24-month-old rats was
significantly decreased
in the cerebellum and mesencephalon compared with the
6-month-old rats (Fig.
6). The heat stability was a little decreased in the
cerebral cortex and
hippocampus of 24-month-old rats. However, the heat
stability was not
decreased in the pons + medulla, striatum, and thalamus of
the 24-month-old
rats.
... It has been reported that the increase in Hsp70 by
a previously
given mild heat stress was effective for reducing the damage
by subsequent
heat and oxidative stresses in mammalian cells ... The
overexpression of
Hsp70 increased the life span of transgenic Drosophila
melanogaster
[http://tinyurl.com/ojc5j and http://tinyurl.com/lapz5 papers]